From 45d25ed4938610d8d0f6fe1a40c7f51df62dc39e Mon Sep 17 00:00:00 2001
From: Christopher Haster <chaster@utexas.edu>
Date: Thu, 18 Aug 2016 13:28:57 -0500
Subject: [PATCH 1/3] Added support for cv-qualifiers in Callback class

Additionally, the following changes were don to avoid combinatorial
explosion in function overloads as a result of adding cv-qualifiers:
- Added convenience function for inferred type
- Deprecated callback overloads qhere cv-qualifiers are not scalable

Supported overloads:
callback(void (*f)(A...));
callback(const Callback<R(A...)> &);
callback(T *t,                void (*f)(T*, A...));
callback(const T *t,          void (*f)(const T*, A...));
callback(volatile T *t,       void (*f)(volatile T*, A...));
callback(const volatile T *t, void (*f)(const volatile T*, A...));
callback(T *t,                void (T::*f)(A...));
callback(const T *t,          void (T::*f)(A...) const);
callback(volatile T *t,       void (T::*f)(A...) volatile);
callback(const volatile T *t, void (T::*f)(A...) const volatile);
---
 TESTS/mbed_drivers/callback/main.cpp |  489 +++--
 features/net/network-socket/Socket.h |   10 +-
 hal/api/CallChain.h                  |   19 +-
 hal/api/Callback.h                   | 2507 ++++++++++++++++++--------
 hal/api/InterruptIn.h                |   17 +-
 hal/api/SerialBase.h                 |   17 +-
 hal/api/Ticker.h                     |   15 +-
 rtos/rtos/RtosTimer.h                |   10 +-
 rtos/rtos/Thread.h                   |   14 +-
 9 files changed, 2131 insertions(+), 967 deletions(-)

diff --git a/TESTS/mbed_drivers/callback/main.cpp b/TESTS/mbed_drivers/callback/main.cpp
index 4e169a5a6c..d4f0e9af57 100644
--- a/TESTS/mbed_drivers/callback/main.cpp
+++ b/TESTS/mbed_drivers/callback/main.cpp
@@ -8,17 +8,17 @@ using namespace utest::v1;
 
 // static functions
 template <typename T>
-T static_func5(T a0, T a1, T a2, T a3, T a4) { return a0 | a1 | a2 | a3 | a4; }
-template <typename T>
-T static_func4(T a0, T a1, T a2, T a3) { return a0 | a1 | a2 | a3; }
-template <typename T>
-T static_func3(T a0, T a1, T a2) { return a0 | a1 | a2; }
-template <typename T>
-T static_func2(T a0, T a1) { return a0 | a1; }
-template <typename T>
-T static_func1(T a0) { return a0; }
-template <typename T>
 T static_func0() { return 0; }
+template <typename T>
+T static_func1(T a0) { return 0 | a0; }
+template <typename T>
+T static_func2(T a0, T a1) { return 0 | a0 | a1; }
+template <typename T>
+T static_func3(T a0, T a1, T a2) { return 0 | a0 | a1 | a2; }
+template <typename T>
+T static_func4(T a0, T a1, T a2, T a3) { return 0 | a0 | a1 | a2 | a3; }
+template <typename T>
+T static_func5(T a0, T a1, T a2, T a3, T a4) { return 0 | a0 | a1 | a2 | a3 | a4; }
 
 // class functions
 template <typename T>
@@ -26,134 +26,95 @@ struct Thing {
     T t;
     Thing() : t(0x80) {}
 
-    T member_func5(T a0, T a1, T a2, T a3, T a4) { return t | a0 | a1 | a2 | a3 | a4; }
-    T member_func4(T a0, T a1, T a2, T a3) { return t | a0 | a1 | a2 | a3; }
-    T member_func3(T a0, T a1, T a2) { return t | a0 | a1 | a2; }
-    T member_func2(T a0, T a1) { return t | a0 | a1; }
-    T member_func1(T a0) { return t | a0; }
     T member_func0() { return t; }
+    T member_func1(T a0) { return t | a0; }
+    T member_func2(T a0, T a1) { return t | a0 | a1; }
+    T member_func3(T a0, T a1, T a2) { return t | a0 | a1 | a2; }
+    T member_func4(T a0, T a1, T a2, T a3) { return t | a0 | a1 | a2 | a3; }
+    T member_func5(T a0, T a1, T a2, T a3, T a4) { return t | a0 | a1 | a2 | a3 | a4; }
+
+    T const_member_func0() const { return t; }
+    T const_member_func1(T a0) const { return t | a0; }
+    T const_member_func2(T a0, T a1) const { return t | a0 | a1; }
+    T const_member_func3(T a0, T a1, T a2) const { return t | a0 | a1 | a2; }
+    T const_member_func4(T a0, T a1, T a2, T a3) const { return t | a0 | a1 | a2 | a3; }
+    T const_member_func5(T a0, T a1, T a2, T a3, T a4) const { return t | a0 | a1 | a2 | a3 | a4; }
+
+    T volatile_member_func0() volatile { return t; }
+    T volatile_member_func1(T a0) volatile { return t | a0; }
+    T volatile_member_func2(T a0, T a1) volatile { return t | a0 | a1; }
+    T volatile_member_func3(T a0, T a1, T a2) volatile { return t | a0 | a1 | a2; }
+    T volatile_member_func4(T a0, T a1, T a2, T a3) volatile { return t | a0 | a1 | a2 | a3; }
+    T volatile_member_func5(T a0, T a1, T a2, T a3, T a4) volatile { return t | a0 | a1 | a2 | a3 | a4; }
+
+    T const_volatile_member_func0() const volatile { return t; }
+    T const_volatile_member_func1(T a0) const volatile { return t | a0; }
+    T const_volatile_member_func2(T a0, T a1) const volatile { return t | a0 | a1; }
+    T const_volatile_member_func3(T a0, T a1, T a2) const volatile { return t | a0 | a1 | a2; }
+    T const_volatile_member_func4(T a0, T a1, T a2, T a3) const volatile { return t | a0 | a1 | a2 | a3; }
+    T const_volatile_member_func5(T a0, T a1, T a2, T a3, T a4) const volatile { return t | a0 | a1 | a2 | a3 | a4; }
 };
 
 // bound functions
 template <typename T>
-T bound_func5(Thing<T> *t, T a0, T a1, T a2, T a3, T a4) { return t->t | a0 | a1 | a2 | a3 | a4; }
-template <typename T>
-T bound_func4(Thing<T> *t, T a0, T a1, T a2, T a3) { return t->t | a0 | a1 | a2 | a3; }
-template <typename T>
-T bound_func3(Thing<T> *t, T a0, T a1, T a2) { return t->t | a0 | a1 | a2; }
-template <typename T>
-T bound_func2(Thing<T> *t, T a0, T a1) { return t->t | a0 | a1; }
+T bound_func0(Thing<T> *t) { return t->t; }
 template <typename T>
 T bound_func1(Thing<T> *t, T a0) { return t->t | a0; }
 template <typename T>
-T bound_func0(Thing<T> *t) { return t->t; }
+T bound_func2(Thing<T> *t, T a0, T a1) { return t->t | a0 | a1; }
+template <typename T>
+T bound_func3(Thing<T> *t, T a0, T a1, T a2) { return t->t | a0 | a1 | a2; }
+template <typename T>
+T bound_func4(Thing<T> *t, T a0, T a1, T a2, T a3) { return t->t | a0 | a1 | a2 | a3; }
+template <typename T>
+T bound_func5(Thing<T> *t, T a0, T a1, T a2, T a3, T a4) { return t->t | a0 | a1 | a2 | a3 | a4; }
 
 // const bound functions
 template <typename T>
-T const_func5(const Thing<T> *t, T a0, T a1, T a2, T a3, T a4) { return t->t | a0 | a1 | a2 | a3 | a4; }
-template <typename T>
-T const_func4(const Thing<T> *t, T a0, T a1, T a2, T a3) { return t->t | a0 | a1 | a2 | a3; }
-template <typename T>
-T const_func3(const Thing<T> *t, T a0, T a1, T a2) { return t->t | a0 | a1 | a2; }
-template <typename T>
-T const_func2(const Thing<T> *t, T a0, T a1) { return t->t | a0 | a1; }
+T const_func0(const Thing<T> *t) { return t->t; }
 template <typename T>
 T const_func1(const Thing<T> *t, T a0) { return t->t | a0; }
 template <typename T>
-T const_func0(const Thing<T> *t) { return t->t; }
+T const_func2(const Thing<T> *t, T a0, T a1) { return t->t | a0 | a1; }
+template <typename T>
+T const_func3(const Thing<T> *t, T a0, T a1, T a2) { return t->t | a0 | a1 | a2; }
+template <typename T>
+T const_func4(const Thing<T> *t, T a0, T a1, T a2, T a3) { return t->t | a0 | a1 | a2 | a3; }
+template <typename T>
+T const_func5(const Thing<T> *t, T a0, T a1, T a2, T a3, T a4) { return t->t | a0 | a1 | a2 | a3 | a4; }
 
 // volatile bound functions
 template <typename T>
-T volatile_func5(volatile Thing<T> *t, T a0, T a1, T a2, T a3, T a4) { return t->t | a0 | a1 | a2 | a3 | a4; }
-template <typename T>
-T volatile_func4(volatile Thing<T> *t, T a0, T a1, T a2, T a3) { return t->t | a0 | a1 | a2 | a3; }
-template <typename T>
-T volatile_func3(volatile Thing<T> *t, T a0, T a1, T a2) { return t->t | a0 | a1 | a2; }
-template <typename T>
-T volatile_func2(volatile Thing<T> *t, T a0, T a1) { return t->t | a0 | a1; }
+T volatile_func0(volatile Thing<T> *t) { return t->t; }
 template <typename T>
 T volatile_func1(volatile Thing<T> *t, T a0) { return t->t | a0; }
 template <typename T>
-T volatile_func0(volatile Thing<T> *t) { return t->t; }
+T volatile_func2(volatile Thing<T> *t, T a0, T a1) { return t->t | a0 | a1; }
+template <typename T>
+T volatile_func3(volatile Thing<T> *t, T a0, T a1, T a2) { return t->t | a0 | a1 | a2; }
+template <typename T>
+T volatile_func4(volatile Thing<T> *t, T a0, T a1, T a2, T a3) { return t->t | a0 | a1 | a2 | a3; }
+template <typename T>
+T volatile_func5(volatile Thing<T> *t, T a0, T a1, T a2, T a3, T a4) { return t->t | a0 | a1 | a2 | a3 | a4; }
 
-// const volatil bound functions
+// const volatile bound functions
 template <typename T>
-T const_volatile_func5(const volatile Thing<T> *t, T a0, T a1, T a2, T a3, T a4) { return t->t | a0 | a1 | a2 | a3 | a4; }
-template <typename T>
-T const_volatile_func4(const volatile Thing<T> *t, T a0, T a1, T a2, T a3) { return t->t | a0 | a1 | a2 | a3; }
-template <typename T>
-T const_volatile_func3(const volatile Thing<T> *t, T a0, T a1, T a2) { return t->t | a0 | a1 | a2; }
-template <typename T>
-T const_volatile_func2(const volatile Thing<T> *t, T a0, T a1) { return t->t | a0 | a1; }
+T const_volatile_func0(const volatile Thing<T> *t) { return t->t; }
 template <typename T>
 T const_volatile_func1(const volatile Thing<T> *t, T a0) { return t->t | a0; }
 template <typename T>
-T const_volatile_func0(const volatile Thing<T> *t) { return t->t; }
+T const_volatile_func2(const volatile Thing<T> *t, T a0, T a1) { return t->t | a0 | a1; }
+template <typename T>
+T const_volatile_func3(const volatile Thing<T> *t, T a0, T a1, T a2) { return t->t | a0 | a1 | a2; }
+template <typename T>
+T const_volatile_func4(const volatile Thing<T> *t, T a0, T a1, T a2, T a3) { return t->t | a0 | a1 | a2 | a3; }
+template <typename T>
+T const_volatile_func5(const volatile Thing<T> *t, T a0, T a1, T a2, T a3, T a4) { return t->t | a0 | a1 | a2 | a3 | a4; }
 
 
 // function call and result verification
 template <typename T>
 struct Verifier {
-    static void verify5(Callback<T(T,T,T,T,T)> func) {
-        T result = func(0x01, 0x02, 0x04, 0x08, 0x10);
-        TEST_ASSERT_EQUAL(result, 0x1f);
-    }
-
-    template <typename O, typename M>
-    static void verify5(O *obj, M method) {
-        Callback<T(T,T,T,T,T)> func(obj, method);
-        T result = func(0x01, 0x02, 0x04, 0x08, 0x10);
-        TEST_ASSERT_EQUAL(result, 0x9f);
-    }
-
-    static void verify4(Callback<T(T,T,T,T)> func) {
-        T result = func(0x01, 0x02, 0x04, 0x08);
-        TEST_ASSERT_EQUAL(result, 0x0f);
-    }
-
-    template <typename O, typename M>
-    static void verify4(O *obj, M method) {
-        Callback<T(T,T,T,T)> func(obj, method);
-        T result = func(0x01, 0x02, 0x04, 0x08);
-        TEST_ASSERT_EQUAL(result, 0x8f);
-    }
-
-    static void verify3(Callback<T(T,T,T)> func) {
-        T result = func(0x01, 0x02, 0x04);
-        TEST_ASSERT_EQUAL(result, 0x07);
-    }
-
-    template <typename O, typename M>
-    static void verify3(O *obj, M method) {
-        Callback<T(T,T,T)> func(obj, method);
-        T result = func(0x01, 0x02, 0x04);
-        TEST_ASSERT_EQUAL(result, 0x87);
-    }
-
-    static void verify2(Callback<T(T,T)> func) {
-        T result = func(0x01, 0x02);
-        TEST_ASSERT_EQUAL(result, 0x03);
-    }
-
-    template <typename O, typename M>
-    static void verify2(O *obj, M method) {
-        Callback<T(T,T)> func(obj, method);
-        T result = func(0x01, 0x02);
-        TEST_ASSERT_EQUAL(result, 0x83);
-    }
-
-    static void verify1(Callback<T(T)> func) {
-        T result = func(0x01);
-        TEST_ASSERT_EQUAL(result, 0x01);
-    }
-
-    template <typename O, typename M>
-    static void verify1(O *obj, M method) {
-        Callback<T(T)> func(obj, method);
-        T result = func(0x01);
-        TEST_ASSERT_EQUAL(result, 0x81);
-    }
-
     static void verify0(Callback<T()> func) {
         T result = func();
         TEST_ASSERT_EQUAL(result, 0x00);
@@ -165,76 +126,97 @@ struct Verifier {
         T result = func();
         TEST_ASSERT_EQUAL(result, 0x80);
     }
+
+    static void verify1(Callback<T(T)> func) {
+        T result = func((1 << 0));
+        TEST_ASSERT_EQUAL(result, 0x00 | (1 << 0));
+    }
+
+    template <typename O, typename M>
+    static void verify1(O *obj, M method) {
+        Callback<T(T)> func(obj, method);
+        T result = func((1 << 0));
+        TEST_ASSERT_EQUAL(result, 0x80 | (1 << 0));
+    }
+
+    static void verify2(Callback<T(T, T)> func) {
+        T result = func((1 << 0), (1 << 1));
+        TEST_ASSERT_EQUAL(result, 0x00 | (1 << 0) | (1 << 1));
+    }
+
+    template <typename O, typename M>
+    static void verify2(O *obj, M method) {
+        Callback<T(T, T)> func(obj, method);
+        T result = func((1 << 0), (1 << 1));
+        TEST_ASSERT_EQUAL(result, 0x80 | (1 << 0) | (1 << 1));
+    }
+
+    static void verify3(Callback<T(T, T, T)> func) {
+        T result = func((1 << 0), (1 << 1), (1 << 2));
+        TEST_ASSERT_EQUAL(result, 0x00 | (1 << 0) | (1 << 1) | (1 << 2));
+    }
+
+    template <typename O, typename M>
+    static void verify3(O *obj, M method) {
+        Callback<T(T, T, T)> func(obj, method);
+        T result = func((1 << 0), (1 << 1), (1 << 2));
+        TEST_ASSERT_EQUAL(result, 0x80 | (1 << 0) | (1 << 1) | (1 << 2));
+    }
+
+    static void verify4(Callback<T(T, T, T, T)> func) {
+        T result = func((1 << 0), (1 << 1), (1 << 2), (1 << 3));
+        TEST_ASSERT_EQUAL(result, 0x00 | (1 << 0) | (1 << 1) | (1 << 2) | (1 << 3));
+    }
+
+    template <typename O, typename M>
+    static void verify4(O *obj, M method) {
+        Callback<T(T, T, T, T)> func(obj, method);
+        T result = func((1 << 0), (1 << 1), (1 << 2), (1 << 3));
+        TEST_ASSERT_EQUAL(result, 0x80 | (1 << 0) | (1 << 1) | (1 << 2) | (1 << 3));
+    }
+
+    static void verify5(Callback<T(T, T, T, T, T)> func) {
+        T result = func((1 << 0), (1 << 1), (1 << 2), (1 << 3), (1 << 4));
+        TEST_ASSERT_EQUAL(result, 0x00 | (1 << 0) | (1 << 1) | (1 << 2) | (1 << 3) | (1 << 4));
+    }
+
+    template <typename O, typename M>
+    static void verify5(O *obj, M method) {
+        Callback<T(T, T, T, T, T)> func(obj, method);
+        T result = func((1 << 0), (1 << 1), (1 << 2), (1 << 3), (1 << 4));
+        TEST_ASSERT_EQUAL(result, 0x80 | (1 << 0) | (1 << 1) | (1 << 2) | (1 << 3) | (1 << 4));
+    }
 };
 
 
 // test dispatch
 template <typename T>
-void test_dispatch5() {
+void test_dispatch0() {
     Thing<T> thing;
-    Verifier<T>::verify5(static_func5<T>);
-    Verifier<T>::verify5(&thing, &Thing<T>::member_func5);
-    Verifier<T>::verify5(&thing, &bound_func5<T>);
-    Verifier<T>::verify5((const Thing<T>*)&thing, &const_func5<T>);
-    Verifier<T>::verify5((volatile Thing<T>*)&thing, &volatile_func5<T>);
-    Verifier<T>::verify5((const volatile Thing<T>*)&thing, &const_volatile_func5<T>);
+    Verifier<T>::verify0(static_func0<T>);
+    Verifier<T>::verify0(&thing, &Thing<T>::member_func0);
+    Verifier<T>::verify0((const Thing<T>*)&thing, &Thing<T>::const_member_func0);
+    Verifier<T>::verify0((volatile Thing<T>*)&thing, &Thing<T>::volatile_member_func0);
+    Verifier<T>::verify0((const volatile Thing<T>*)&thing, &Thing<T>::const_volatile_member_func0);
+    Verifier<T>::verify0(&thing, &bound_func0<T>);
+    Verifier<T>::verify0((const Thing<T>*)&thing, &const_func0<T>);
+    Verifier<T>::verify0((volatile Thing<T>*)&thing, &volatile_func0<T>);
+    Verifier<T>::verify0((const volatile Thing<T>*)&thing, &const_volatile_func0<T>);
+    Verifier<T>::verify0(callback(static_func0<T>));
+    Verifier<T>::verify0(callback(&thing, &Thing<T>::member_func0));
+    Verifier<T>::verify0(callback((const Thing<T>*)&thing, &Thing<T>::const_member_func0));
+    Verifier<T>::verify0(callback((volatile Thing<T>*)&thing, &Thing<T>::volatile_member_func0));
+    Verifier<T>::verify0(callback((const volatile Thing<T>*)&thing, &Thing<T>::const_volatile_member_func0));
+    Verifier<T>::verify0(callback(&thing, &bound_func0<T>));
+    Verifier<T>::verify0(callback((const Thing<T>*)&thing, &const_func0<T>));
+    Verifier<T>::verify0(callback((volatile Thing<T>*)&thing, &volatile_func0<T>));
+    Verifier<T>::verify0(callback((const volatile Thing<T>*)&thing, &const_volatile_func0<T>));
 
-    Callback<T(T,T,T,T,T)> callback(static_func5);
-    Verifier<T>::verify5(callback);
-    callback.attach(&thing, &bound_func5<T>);
-    Verifier<T>::verify5(&callback, &Callback<T(T,T,T,T,T)>::call);
-    Verifier<T>::verify5((void*)&callback, &Callback<T(T,T,T,T,T)>::thunk);
-}
-
-template <typename T>
-void test_dispatch4() {
-    Thing<T> thing;
-    Verifier<T>::verify4(static_func4<T>);
-    Verifier<T>::verify4(&thing, &Thing<T>::member_func4);
-    Verifier<T>::verify4(&thing, &bound_func4<T>);
-    Verifier<T>::verify4((const Thing<T>*)&thing, &const_func4<T>);
-    Verifier<T>::verify4((volatile Thing<T>*)&thing, &volatile_func4<T>);
-    Verifier<T>::verify4((const volatile Thing<T>*)&thing, &const_volatile_func4<T>);
-
-    Callback<T(T,T,T,T)> callback(static_func4);
-    Verifier<T>::verify4(callback);
-    callback.attach(&thing, &bound_func4<T>);
-    Verifier<T>::verify4(&callback, &Callback<T(T,T,T,T)>::call);
-    Verifier<T>::verify4((void*)&callback, &Callback<T(T,T,T,T)>::thunk);
-}
-
-template <typename T>
-void test_dispatch3() {
-    Thing<T> thing;
-    Verifier<T>::verify3(static_func3<T>);
-    Verifier<T>::verify3(&thing, &Thing<T>::member_func3);
-    Verifier<T>::verify3(&thing, &bound_func3<T>);
-    Verifier<T>::verify3((const Thing<T>*)&thing, &const_func3<T>);
-    Verifier<T>::verify3((volatile Thing<T>*)&thing, &volatile_func3<T>);
-    Verifier<T>::verify3((const volatile Thing<T>*)&thing, &const_volatile_func3<T>);
-
-    Callback<T(T,T,T)> callback(static_func3);
-    Verifier<T>::verify3(callback);
-    callback.attach(&thing, &bound_func3<T>);
-    Verifier<T>::verify3(&callback, &Callback<T(T,T,T)>::call);
-    Verifier<T>::verify3((void*)&callback, &Callback<T(T,T,T)>::thunk);
-}
-
-template <typename T>
-void test_dispatch2() {
-    Thing<T> thing;
-    Verifier<T>::verify2(static_func2<T>);
-    Verifier<T>::verify2(&thing, &Thing<T>::member_func2);
-    Verifier<T>::verify2(&thing, &bound_func2<T>);
-    Verifier<T>::verify2((const Thing<T>*)&thing, &const_func2<T>);
-    Verifier<T>::verify2((volatile Thing<T>*)&thing, &volatile_func2<T>);
-    Verifier<T>::verify2((const volatile Thing<T>*)&thing, &const_volatile_func2<T>);
-
-    Callback<T(T,T)> callback(static_func2);
-    Verifier<T>::verify2(callback);
-    callback.attach(&thing, &bound_func2<T>);
-    Verifier<T>::verify2(&callback, &Callback<T(T,T)>::call);
-    Verifier<T>::verify2((void*)&callback, &Callback<T(T,T)>::thunk);
+    Callback<T()> callback(static_func0);
+    Verifier<T>::verify0(callback);
+    callback.attach(&thing, &bound_func0<T>);
+    Verifier<T>::verify0(&callback, &Callback<T()>::call);
+    Verifier<T>::verify0((void*)&callback, &Callback<T()>::thunk);
 }
 
 template <typename T>
@@ -242,10 +224,22 @@ void test_dispatch1() {
     Thing<T> thing;
     Verifier<T>::verify1(static_func1<T>);
     Verifier<T>::verify1(&thing, &Thing<T>::member_func1);
+    Verifier<T>::verify1((const Thing<T>*)&thing, &Thing<T>::const_member_func1);
+    Verifier<T>::verify1((volatile Thing<T>*)&thing, &Thing<T>::volatile_member_func1);
+    Verifier<T>::verify1((const volatile Thing<T>*)&thing, &Thing<T>::const_volatile_member_func1);
     Verifier<T>::verify1(&thing, &bound_func1<T>);
     Verifier<T>::verify1((const Thing<T>*)&thing, &const_func1<T>);
     Verifier<T>::verify1((volatile Thing<T>*)&thing, &volatile_func1<T>);
     Verifier<T>::verify1((const volatile Thing<T>*)&thing, &const_volatile_func1<T>);
+    Verifier<T>::verify1(callback(static_func1<T>));
+    Verifier<T>::verify1(callback(&thing, &Thing<T>::member_func1));
+    Verifier<T>::verify1(callback((const Thing<T>*)&thing, &Thing<T>::const_member_func1));
+    Verifier<T>::verify1(callback((volatile Thing<T>*)&thing, &Thing<T>::volatile_member_func1));
+    Verifier<T>::verify1(callback((const volatile Thing<T>*)&thing, &Thing<T>::const_volatile_member_func1));
+    Verifier<T>::verify1(callback(&thing, &bound_func1<T>));
+    Verifier<T>::verify1(callback((const Thing<T>*)&thing, &const_func1<T>));
+    Verifier<T>::verify1(callback((volatile Thing<T>*)&thing, &volatile_func1<T>));
+    Verifier<T>::verify1(callback((const volatile Thing<T>*)&thing, &const_volatile_func1<T>));
 
     Callback<T(T)> callback(static_func1);
     Verifier<T>::verify1(callback);
@@ -255,20 +249,119 @@ void test_dispatch1() {
 }
 
 template <typename T>
-void test_dispatch0() {
+void test_dispatch2() {
     Thing<T> thing;
-    Verifier<T>::verify0(static_func0<T>);
-    Verifier<T>::verify0(&thing, &Thing<T>::member_func0);
-    Verifier<T>::verify0(&thing, &bound_func0<T>);
-    Verifier<T>::verify0((const Thing<T>*)&thing, &const_func0<T>);
-    Verifier<T>::verify0((volatile Thing<T>*)&thing, &volatile_func0<T>);
-    Verifier<T>::verify0((const volatile Thing<T>*)&thing, &const_volatile_func0<T>);
+    Verifier<T>::verify2(static_func2<T>);
+    Verifier<T>::verify2(&thing, &Thing<T>::member_func2);
+    Verifier<T>::verify2((const Thing<T>*)&thing, &Thing<T>::const_member_func2);
+    Verifier<T>::verify2((volatile Thing<T>*)&thing, &Thing<T>::volatile_member_func2);
+    Verifier<T>::verify2((const volatile Thing<T>*)&thing, &Thing<T>::const_volatile_member_func2);
+    Verifier<T>::verify2(&thing, &bound_func2<T>);
+    Verifier<T>::verify2((const Thing<T>*)&thing, &const_func2<T>);
+    Verifier<T>::verify2((volatile Thing<T>*)&thing, &volatile_func2<T>);
+    Verifier<T>::verify2((const volatile Thing<T>*)&thing, &const_volatile_func2<T>);
+    Verifier<T>::verify2(callback(static_func2<T>));
+    Verifier<T>::verify2(callback(&thing, &Thing<T>::member_func2));
+    Verifier<T>::verify2(callback((const Thing<T>*)&thing, &Thing<T>::const_member_func2));
+    Verifier<T>::verify2(callback((volatile Thing<T>*)&thing, &Thing<T>::volatile_member_func2));
+    Verifier<T>::verify2(callback((const volatile Thing<T>*)&thing, &Thing<T>::const_volatile_member_func2));
+    Verifier<T>::verify2(callback(&thing, &bound_func2<T>));
+    Verifier<T>::verify2(callback((const Thing<T>*)&thing, &const_func2<T>));
+    Verifier<T>::verify2(callback((volatile Thing<T>*)&thing, &volatile_func2<T>));
+    Verifier<T>::verify2(callback((const volatile Thing<T>*)&thing, &const_volatile_func2<T>));
 
-    Callback<T()> callback(static_func0);
-    Verifier<T>::verify0(callback);
-    callback.attach(&thing, &bound_func0<T>);
-    Verifier<T>::verify0(&callback, &Callback<T()>::call);
-    Verifier<T>::verify0((void*)&callback, &Callback<T()>::thunk);
+    Callback<T(T, T)> callback(static_func2);
+    Verifier<T>::verify2(callback);
+    callback.attach(&thing, &bound_func2<T>);
+    Verifier<T>::verify2(&callback, &Callback<T(T, T)>::call);
+    Verifier<T>::verify2((void*)&callback, &Callback<T(T, T)>::thunk);
+}
+
+template <typename T>
+void test_dispatch3() {
+    Thing<T> thing;
+    Verifier<T>::verify3(static_func3<T>);
+    Verifier<T>::verify3(&thing, &Thing<T>::member_func3);
+    Verifier<T>::verify3((const Thing<T>*)&thing, &Thing<T>::const_member_func3);
+    Verifier<T>::verify3((volatile Thing<T>*)&thing, &Thing<T>::volatile_member_func3);
+    Verifier<T>::verify3((const volatile Thing<T>*)&thing, &Thing<T>::const_volatile_member_func3);
+    Verifier<T>::verify3(&thing, &bound_func3<T>);
+    Verifier<T>::verify3((const Thing<T>*)&thing, &const_func3<T>);
+    Verifier<T>::verify3((volatile Thing<T>*)&thing, &volatile_func3<T>);
+    Verifier<T>::verify3((const volatile Thing<T>*)&thing, &const_volatile_func3<T>);
+    Verifier<T>::verify3(callback(static_func3<T>));
+    Verifier<T>::verify3(callback(&thing, &Thing<T>::member_func3));
+    Verifier<T>::verify3(callback((const Thing<T>*)&thing, &Thing<T>::const_member_func3));
+    Verifier<T>::verify3(callback((volatile Thing<T>*)&thing, &Thing<T>::volatile_member_func3));
+    Verifier<T>::verify3(callback((const volatile Thing<T>*)&thing, &Thing<T>::const_volatile_member_func3));
+    Verifier<T>::verify3(callback(&thing, &bound_func3<T>));
+    Verifier<T>::verify3(callback((const Thing<T>*)&thing, &const_func3<T>));
+    Verifier<T>::verify3(callback((volatile Thing<T>*)&thing, &volatile_func3<T>));
+    Verifier<T>::verify3(callback((const volatile Thing<T>*)&thing, &const_volatile_func3<T>));
+
+    Callback<T(T, T, T)> callback(static_func3);
+    Verifier<T>::verify3(callback);
+    callback.attach(&thing, &bound_func3<T>);
+    Verifier<T>::verify3(&callback, &Callback<T(T, T, T)>::call);
+    Verifier<T>::verify3((void*)&callback, &Callback<T(T, T, T)>::thunk);
+}
+
+template <typename T>
+void test_dispatch4() {
+    Thing<T> thing;
+    Verifier<T>::verify4(static_func4<T>);
+    Verifier<T>::verify4(&thing, &Thing<T>::member_func4);
+    Verifier<T>::verify4((const Thing<T>*)&thing, &Thing<T>::const_member_func4);
+    Verifier<T>::verify4((volatile Thing<T>*)&thing, &Thing<T>::volatile_member_func4);
+    Verifier<T>::verify4((const volatile Thing<T>*)&thing, &Thing<T>::const_volatile_member_func4);
+    Verifier<T>::verify4(&thing, &bound_func4<T>);
+    Verifier<T>::verify4((const Thing<T>*)&thing, &const_func4<T>);
+    Verifier<T>::verify4((volatile Thing<T>*)&thing, &volatile_func4<T>);
+    Verifier<T>::verify4((const volatile Thing<T>*)&thing, &const_volatile_func4<T>);
+    Verifier<T>::verify4(callback(static_func4<T>));
+    Verifier<T>::verify4(callback(&thing, &Thing<T>::member_func4));
+    Verifier<T>::verify4(callback((const Thing<T>*)&thing, &Thing<T>::const_member_func4));
+    Verifier<T>::verify4(callback((volatile Thing<T>*)&thing, &Thing<T>::volatile_member_func4));
+    Verifier<T>::verify4(callback((const volatile Thing<T>*)&thing, &Thing<T>::const_volatile_member_func4));
+    Verifier<T>::verify4(callback(&thing, &bound_func4<T>));
+    Verifier<T>::verify4(callback((const Thing<T>*)&thing, &const_func4<T>));
+    Verifier<T>::verify4(callback((volatile Thing<T>*)&thing, &volatile_func4<T>));
+    Verifier<T>::verify4(callback((const volatile Thing<T>*)&thing, &const_volatile_func4<T>));
+
+    Callback<T(T, T, T, T)> callback(static_func4);
+    Verifier<T>::verify4(callback);
+    callback.attach(&thing, &bound_func4<T>);
+    Verifier<T>::verify4(&callback, &Callback<T(T, T, T, T)>::call);
+    Verifier<T>::verify4((void*)&callback, &Callback<T(T, T, T, T)>::thunk);
+}
+
+template <typename T>
+void test_dispatch5() {
+    Thing<T> thing;
+    Verifier<T>::verify5(static_func5<T>);
+    Verifier<T>::verify5(&thing, &Thing<T>::member_func5);
+    Verifier<T>::verify5((const Thing<T>*)&thing, &Thing<T>::const_member_func5);
+    Verifier<T>::verify5((volatile Thing<T>*)&thing, &Thing<T>::volatile_member_func5);
+    Verifier<T>::verify5((const volatile Thing<T>*)&thing, &Thing<T>::const_volatile_member_func5);
+    Verifier<T>::verify5(&thing, &bound_func5<T>);
+    Verifier<T>::verify5((const Thing<T>*)&thing, &const_func5<T>);
+    Verifier<T>::verify5((volatile Thing<T>*)&thing, &volatile_func5<T>);
+    Verifier<T>::verify5((const volatile Thing<T>*)&thing, &const_volatile_func5<T>);
+    Verifier<T>::verify5(callback(static_func5<T>));
+    Verifier<T>::verify5(callback(&thing, &Thing<T>::member_func5));
+    Verifier<T>::verify5(callback((const Thing<T>*)&thing, &Thing<T>::const_member_func5));
+    Verifier<T>::verify5(callback((volatile Thing<T>*)&thing, &Thing<T>::volatile_member_func5));
+    Verifier<T>::verify5(callback((const volatile Thing<T>*)&thing, &Thing<T>::const_volatile_member_func5));
+    Verifier<T>::verify5(callback(&thing, &bound_func5<T>));
+    Verifier<T>::verify5(callback((const Thing<T>*)&thing, &const_func5<T>));
+    Verifier<T>::verify5(callback((volatile Thing<T>*)&thing, &volatile_func5<T>));
+    Verifier<T>::verify5(callback((const volatile Thing<T>*)&thing, &const_volatile_func5<T>));
+
+    Callback<T(T, T, T, T, T)> callback(static_func5);
+    Verifier<T>::verify5(callback);
+    callback.attach(&thing, &bound_func5<T>);
+    Verifier<T>::verify5(&callback, &Callback<T(T, T, T, T, T)>::call);
+    Verifier<T>::verify5((void*)&callback, &Callback<T(T, T, T, T, T)>::thunk);
 }
 
 template <typename T>
@@ -295,26 +388,26 @@ utest::v1::status_t test_setup(const size_t number_of_cases) {
 }
 
 Case cases[] = {
-    Case("Testing callbacks with 5 ints", test_dispatch5<int>),
-    Case("Testing callbacks with 4 ints", test_dispatch4<int>),
-    Case("Testing callbacks with 3 ints", test_dispatch3<int>),
-    Case("Testing callbacks with 2 ints", test_dispatch2<int>),
-    Case("Testing callbacks with 1 ints", test_dispatch1<int>),
     Case("Testing callbacks with 0 ints", test_dispatch0<int>),
+    Case("Testing callbacks with 1 ints", test_dispatch1<int>),
+    Case("Testing callbacks with 2 ints", test_dispatch2<int>),
+    Case("Testing callbacks with 3 ints", test_dispatch3<int>),
+    Case("Testing callbacks with 4 ints", test_dispatch4<int>),
+    Case("Testing callbacks with 5 ints", test_dispatch5<int>),
 
-    Case("Testing callbacks with 5 uchars", test_dispatch5<unsigned char>),
-    Case("Testing callbacks with 4 uchars", test_dispatch4<unsigned char>),
-    Case("Testing callbacks with 3 uchars", test_dispatch3<unsigned char>),
-    Case("Testing callbacks with 2 uchars", test_dispatch2<unsigned char>),
-    Case("Testing callbacks with 1 uchars", test_dispatch1<unsigned char>),
     Case("Testing callbacks with 0 uchars", test_dispatch0<unsigned char>),
+    Case("Testing callbacks with 1 uchars", test_dispatch1<unsigned char>),
+    Case("Testing callbacks with 2 uchars", test_dispatch2<unsigned char>),
+    Case("Testing callbacks with 3 uchars", test_dispatch3<unsigned char>),
+    Case("Testing callbacks with 4 uchars", test_dispatch4<unsigned char>),
+    Case("Testing callbacks with 5 uchars", test_dispatch5<unsigned char>),
 
-    Case("Testing callbacks with 5 uint64s", test_dispatch5<uint64_t>),
-    Case("Testing callbacks with 4 uint64s", test_dispatch4<uint64_t>),
-    Case("Testing callbacks with 3 uint64s", test_dispatch3<uint64_t>),
-    Case("Testing callbacks with 2 uint64s", test_dispatch2<uint64_t>),
-    Case("Testing callbacks with 1 uint64s", test_dispatch1<uint64_t>),
     Case("Testing callbacks with 0 uint64s", test_dispatch0<uint64_t>),
+    Case("Testing callbacks with 1 uint64s", test_dispatch1<uint64_t>),
+    Case("Testing callbacks with 2 uint64s", test_dispatch2<uint64_t>),
+    Case("Testing callbacks with 3 uint64s", test_dispatch3<uint64_t>),
+    Case("Testing callbacks with 4 uint64s", test_dispatch4<uint64_t>),
+    Case("Testing callbacks with 5 uint64s", test_dispatch5<uint64_t>),
 
     Case("Testing FunctionPointerArg1 compatibility", test_fparg1<int>),
     Case("Testing FunctionPointer compatibility", test_fparg0<int>),
diff --git a/features/net/network-socket/Socket.h b/features/net/network-socket/Socket.h
index c481930440..39a89a529f 100644
--- a/features/net/network-socket/Socket.h
+++ b/features/net/network-socket/Socket.h
@@ -21,6 +21,7 @@
 #include "network-socket/NetworkStack.h"
 #include "rtos/Mutex.h"
 #include "Callback.h"
+#include "toolchain.h"
 
 
 /** Abstract socket class
@@ -168,10 +169,17 @@ public:
      *
      *  @param obj      Pointer to object to call method on
      *  @param method   Method to call on state change
+     *
+     *  @deprecated
+     *      The attach function does not support cv-qualifiers. Replaced by
+     *      attach(callback(obj, method)).
      */
     template <typename T, typename M>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+        "The attach function does not support cv-qualifiers. Replaced by "
+        "attach(callback(obj, method)).")
     void attach(T *obj, M method) {
-        attach(mbed::Callback<void()>(obj, method));
+        attach(mbed::callback(obj, method));
     }
 
 protected:
diff --git a/hal/api/CallChain.h b/hal/api/CallChain.h
index 473ff12a14..7b0b20edc5 100644
--- a/hal/api/CallChain.h
+++ b/hal/api/CallChain.h
@@ -17,6 +17,7 @@
 #define MBED_CALLCHAIN_H
 
 #include "Callback.h"
+#include "toolchain.h"
 #include <string.h>
 
 namespace mbed {
@@ -87,10 +88,17 @@ public:
      *
      *  @returns
      *  The function object created for 'obj' and 'method'
+     *
+     *  @deprecated
+     *  The add function does not support cv-qualifiers. Replaced by
+     *  add(callback(obj, method)).
      */
     template<typename T, typename M>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+        "The add function does not support cv-qualifiers. Replaced by "
+        "add(callback(obj, method)).")
     pFunctionPointer_t add(T *obj, M method) {
-        return add(Callback<void()>(obj, method));
+        return add(callback(obj, method));
     }
 
     /** Add a function at the beginning of the chain
@@ -109,10 +117,17 @@ public:
      *
      *  @returns
      *  The function object created for 'tptr' and 'mptr'
+     *
+     *  @deprecated
+     *  The add_front function does not support cv-qualifiers. Replaced by
+     *  add_front(callback(obj, method)).
      */
     template<typename T, typename M>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+        "The add_front function does not support cv-qualifiers. Replaced by "
+        "add_front(callback(obj, method)).")
     pFunctionPointer_t add_front(T *obj, M method) {
-        return add_front(Callback<void()>(obj, method));
+        return add_front(callback(obj, method));
     }
 
     /** Get the number of functions in the chain
diff --git a/hal/api/Callback.h b/hal/api/Callback.h
index 8ffd70164c..8a415bb6c4 100644
--- a/hal/api/Callback.h
+++ b/hal/api/Callback.h
@@ -29,711 +29,6 @@ namespace mbed {
 template <typename F>
 class Callback;
 
-/** Templated function class
- */
-template <typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
-class Callback<R(A0, A1, A2, A3, A4)> {
-public:
-    /** Create a Callback with a static function
-     *  @param func Static function to attach
-     */
-    Callback(R (*func)(A0, A1, A2, A3, A4) = 0) {
-        attach(func);
-    }
-
-    /** Create a Callback with a static function and bound pointer
-     *  @param obj  Pointer to object to bind to function
-     *  @param func Static function to attach
-     */
-    template<typename T>
-    Callback(T *obj, R (*func)(T*, A0, A1, A2, A3, A4)) {
-        attach(obj, func);
-    }
-
-    /** Create a Callback with a member function
-     *  @param obj  Pointer to object to invoke member function on
-     *  @param func Member function to attach
-     */
-    template<typename T>
-    Callback(T *obj, R (T::*func)(A0, A1, A2, A3, A4)) {
-        attach(obj, func);
-    }
-
-    /** Create a Callback with another Callback
-     *  @param func Callback to attach
-     */
-    Callback(const Callback<R(A0, A1, A2, A3, A4)> &func) {
-        attach(func);
-    }
-
-    /** Attach a static function
-     *  @param func Static function to attach
-     */
-    void attach(R (*func)(A0, A1, A2, A3, A4)) {
-        memcpy(&_func, &func, sizeof func);
-        _thunk = func ? &Callback::_staticthunk : 0;
-    }
-
-    /** Attach a static function with a bound pointer
-     *  @param obj  Pointer to object to bind to function
-     *  @param func Static function to attach
-     */
-    template <typename T>
-    void attach(T *obj, R (*func)(T*, A0, A1, A2, A3, A4)) {
-        _obj = (void*)obj;
-        memcpy(&_func, &func, sizeof func);
-        _thunk = &Callback::_boundthunk<T>;
-    }
-
-    /** Attach a member function
-     *  @param obj  Pointer to object to invoke member function on
-     *  @param func Member function to attach
-     */
-    template<typename T>
-    void attach(T *obj, R (T::*func)(A0, A1, A2, A3, A4)) {
-        _obj = static_cast<void*>(obj);
-        memcpy(&_func, &func, sizeof func);
-        _thunk = &Callback::_methodthunk<T>;
-    }
-
-    /** Attach a Callback
-     *  @param func The Callback to attach
-     */
-    void attach(const Callback<R(A0, A1, A2, A3, A4)> &func) {
-        _obj = func._obj;
-        memcpy(&_func, &func._func, sizeof _func);
-        _thunk = func._thunk;
-    }
-
-    /** Call the attached function
-     */
-    R call(A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
-        if (!_thunk) {
-            return (R)0;
-        }
-        return _thunk(_obj, &_func, a0, a1, a2, a3, a4);
-    }
-
-    /** Call the attached function
-     */
-    R operator()(A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
-        return call(a0, a1, a2, a3, a4);
-    }
-
-    /** Test if function has been attached
-     */
-    operator bool() const {
-        return _thunk;
-    }
-
-    /** Static thunk for passing as C-style function
-     *  @param func Callback to call passed as void pointer
-     */
-    static R thunk(void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
-        return static_cast<Callback<R(A0, A1, A2, A3, A4)>*>(func)
-                ->call(a0, a1, a2, a3, a4);
-    }
-
-private:
-    // Internal thunks for various function types
-    static R _staticthunk(void*, void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
-        return (*reinterpret_cast<R (**)(A0, A1, A2, A3, A4)>(func))
-                (a0, a1, a2, a3, a4);
-    }
-
-    template<typename T>
-    static R _boundthunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
-        return (*reinterpret_cast<R (**)(T*, A0, A1, A2, A3, A4)>(func))
-                (static_cast<T*>(obj), a0, a1, a2, a3, a4);
-    }
-
-    template<typename T>
-    static R _methodthunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
-        return (static_cast<T*>(obj)->*
-                (*reinterpret_cast<R (T::**)(A0, A1, A2, A3, A4)>(func)))
-                (a0, a1, a2, a3, a4);
-    }
-
-    // Stored as pointer to function and pointer to optional object
-    // Function pointer is stored as union of possible function types
-    // to garuntee proper size and alignment
-    struct _class;
-    union {
-        void (*_staticfunc)();
-        void (*_boundfunc)(_class *);
-        void (_class::*_methodfunc)();
-    } _func;
-
-    void *_obj;
-
-    // Thunk registered on attach to dispatch calls
-    R (*_thunk)(void*, void*, A0, A1, A2, A3, A4); 
-};
-
-/** Templated function class
- */
-template <typename R, typename A0, typename A1, typename A2, typename A3>
-class Callback<R(A0, A1, A2, A3)> {
-public:
-    /** Create a Callback with a static function
-     *  @param func Static function to attach
-     */
-    Callback(R (*func)(A0, A1, A2, A3) = 0) {
-        attach(func);
-    }
-
-    /** Create a Callback with a static function and bound pointer
-     *  @param obj  Pointer to object to bind to function
-     *  @param func Static function to attach
-     */
-    template<typename T>
-    Callback(T *obj, R (*func)(T*, A0, A1, A2, A3)) {
-        attach(obj, func);
-    }
-
-    /** Create a Callback with a member function
-     *  @param obj  Pointer to object to invoke member function on
-     *  @param func Member function to attach
-     */
-    template<typename T>
-    Callback(T *obj, R (T::*func)(A0, A1, A2, A3)) {
-        attach(obj, func);
-    }
-
-    /** Create a Callback with another Callback
-     *  @param func Callback to attach
-     */
-    Callback(const Callback<R(A0, A1, A2, A3)> &func) {
-        attach(func);
-    }
-
-    /** Attach a static function
-     *  @param func Static function to attach
-     */
-    void attach(R (*func)(A0, A1, A2, A3)) {
-        memcpy(&_func, &func, sizeof func);
-        _thunk = func ? &Callback::_staticthunk : 0;
-    }
-
-    /** Attach a static function with a bound pointer
-     *  @param obj  Pointer to object to bind to function
-     *  @param func Static function to attach
-     */
-    template <typename T>
-    void attach(T *obj, R (*func)(T*, A0, A1, A2, A3)) {
-        _obj = (void*)obj;
-        memcpy(&_func, &func, sizeof func);
-        _thunk = &Callback::_boundthunk<T>;
-    }
-
-    /** Attach a member function
-     *  @param obj  Pointer to object to invoke member function on
-     *  @param func Member function to attach
-     */
-    template<typename T>
-    void attach(T *obj, R (T::*func)(A0, A1, A2, A3)) {
-        _obj = static_cast<void*>(obj);
-        memcpy(&_func, &func, sizeof func);
-        _thunk = &Callback::_methodthunk<T>;
-    }
-
-    /** Attach a Callback
-     *  @param func The Callback to attach
-     */
-    void attach(const Callback<R(A0, A1, A2, A3)> &func) {
-        _obj = func._obj;
-        memcpy(&_func, &func._func, sizeof _func);
-        _thunk = func._thunk;
-    }
-
-    /** Call the attached function
-     */
-    R call(A0 a0, A1 a1, A2 a2, A3 a3) {
-        if (!_thunk) {
-            return (R)0;
-        }
-        return _thunk(_obj, &_func, a0, a1, a2, a3);
-    }
-
-    /** Call the attached function
-     */
-    R operator()(A0 a0, A1 a1, A2 a2, A3 a3) {
-        return call(a0, a1, a2, a3);
-    }
-
-    /** Test if function has been attached
-     */
-    operator bool() const {
-        return _thunk;
-    }
-
-    /** Static thunk for passing as C-style function
-     *  @param func Callback to call passed as void pointer
-     */
-    static R thunk(void *func, A0 a0, A1 a1, A2 a2, A3 a3) {
-        return static_cast<Callback<R(A0, A1, A2, A3)>*>(func)
-                ->call(a0, a1, a2, a3);
-    }
-
-private:
-    // Internal thunks for various function types
-    static R _staticthunk(void*, void *func, A0 a0, A1 a1, A2 a2, A3 a3) {
-        return (*reinterpret_cast<R (**)(A0, A1, A2, A3)>(func))
-                (a0, a1, a2, a3);
-    }
-
-    template<typename T>
-    static R _boundthunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3) {
-        return (*reinterpret_cast<R (**)(T*, A0, A1, A2, A3)>(func))
-                (static_cast<T*>(obj), a0, a1, a2, a3);
-    }
-
-    template<typename T>
-    static R _methodthunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3) {
-        return (static_cast<T*>(obj)->*
-                (*reinterpret_cast<R (T::**)(A0, A1, A2, A3)>(func)))
-                (a0, a1, a2, a3);
-    }
-
-    // Stored as pointer to function and pointer to optional object
-    // Function pointer is stored as union of possible function types
-    // to garuntee proper size and alignment
-    struct _class;
-    union {
-        void (*_staticfunc)();
-        void (*_boundfunc)(_class *);
-        void (_class::*_methodfunc)();
-    } _func;
-
-    void *_obj;
-
-    // Thunk registered on attach to dispatch calls
-    R (*_thunk)(void*, void*, A0, A1, A2, A3); 
-};
-
-/** Templated function class
- */
-template <typename R, typename A0, typename A1, typename A2>
-class Callback<R(A0, A1, A2)> {
-public:
-    /** Create a Callback with a static function
-     *  @param func Static function to attach
-     */
-    Callback(R (*func)(A0, A1, A2) = 0) {
-        attach(func);
-    }
-
-    /** Create a Callback with a static function and bound pointer
-     *  @param obj  Pointer to object to bind to function
-     *  @param func Static function to attach
-     */
-    template<typename T>
-    Callback(T *obj, R (*func)(T*, A0, A1, A2)) {
-        attach(obj, func);
-    }
-
-    /** Create a Callback with a member function
-     *  @param obj  Pointer to object to invoke member function on
-     *  @param func Member function to attach
-     */
-    template<typename T>
-    Callback(T *obj, R (T::*func)(A0, A1, A2)) {
-        attach(obj, func);
-    }
-
-    /** Create a Callback with another Callback
-     *  @param func Callback to attach
-     */
-    Callback(const Callback<R(A0, A1, A2)> &func) {
-        attach(func);
-    }
-
-    /** Attach a static function
-     *  @param func Static function to attach
-     */
-    void attach(R (*func)(A0, A1, A2)) {
-        memcpy(&_func, &func, sizeof func);
-        _thunk = func ? &Callback::_staticthunk : 0;
-    }
-
-    /** Attach a static function with a bound pointer
-     *  @param obj  Pointer to object to bind to function
-     *  @param func Static function to attach
-     */
-    template <typename T>
-    void attach(T *obj, R (*func)(T*, A0, A1, A2)) {
-        _obj = (void*)obj;
-        memcpy(&_func, &func, sizeof func);
-        _thunk = &Callback::_boundthunk<T>;
-    }
-
-    /** Attach a member function
-     *  @param obj  Pointer to object to invoke member function on
-     *  @param func Member function to attach
-     */
-    template<typename T>
-    void attach(T *obj, R (T::*func)(A0, A1, A2)) {
-        _obj = static_cast<void*>(obj);
-        memcpy(&_func, &func, sizeof func);
-        _thunk = &Callback::_methodthunk<T>;
-    }
-
-    /** Attach a Callback
-     *  @param func The Callback to attach
-     */
-    void attach(const Callback<R(A0, A1, A2)> &func) {
-        _obj = func._obj;
-        memcpy(&_func, &func._func, sizeof _func);
-        _thunk = func._thunk;
-    }
-
-    /** Call the attached function
-     */
-    R call(A0 a0, A1 a1, A2 a2) {
-        if (!_thunk) {
-            return (R)0;
-        }
-        return _thunk(_obj, &_func, a0, a1, a2);
-    }
-
-    /** Call the attached function
-     */
-    R operator()(A0 a0, A1 a1, A2 a2) {
-        return call(a0, a1, a2);
-    }
-
-    /** Test if function has been attached
-     */
-    operator bool() const {
-        return _thunk;
-    }
-
-    /** Static thunk for passing as C-style function
-     *  @param func Callback to call passed as void pointer
-     */
-    static R thunk(void *func, A0 a0, A1 a1, A2 a2) {
-        return static_cast<Callback<R(A0, A1, A2)>*>(func)
-                ->call(a0, a1, a2);
-    }
-
-private:
-    // Internal thunks for various function types
-    static R _staticthunk(void*, void *func, A0 a0, A1 a1, A2 a2) {
-        return (*reinterpret_cast<R (**)(A0, A1, A2)>(func))
-                (a0, a1, a2);
-    }
-
-    template<typename T>
-    static R _boundthunk(void *obj, void *func, A0 a0, A1 a1, A2 a2) {
-        return (*reinterpret_cast<R (**)(T*, A0, A1, A2)>(func))
-                (static_cast<T*>(obj), a0, a1, a2);
-    }
-
-    template<typename T>
-    static R _methodthunk(void *obj, void *func, A0 a0, A1 a1, A2 a2) {
-        return (static_cast<T*>(obj)->*
-                (*reinterpret_cast<R (T::**)(A0, A1, A2)>(func)))
-                (a0, a1, a2);
-    }
-
-    // Stored as pointer to function and pointer to optional object
-    // Function pointer is stored as union of possible function types
-    // to garuntee proper size and alignment
-    struct _class;
-    union {
-        void (*_staticfunc)();
-        void (*_boundfunc)(_class *);
-        void (_class::*_methodfunc)();
-    } _func;
-
-    void *_obj;
-
-    // Thunk registered on attach to dispatch calls
-    R (*_thunk)(void*, void*, A0, A1, A2);
-};
-
-/** Templated function class
- */
-template <typename R, typename A0, typename A1>
-class Callback<R(A0, A1)> {
-public:
-    /** Create a Callback with a static function
-     *  @param func Static function to attach
-     */
-    Callback(R (*func)(A0, A1) = 0) {
-        attach(func);
-    }
-
-    /** Create a Callback with a static function and bound pointer
-     *  @param obj  Pointer to object to bind to function
-     *  @param func Static function to attach
-     */
-    template<typename T>
-    Callback(T *obj, R (*func)(T*, A0, A1)) {
-        attach(obj, func);
-    }
-
-    /** Create a Callback with a member function
-     *  @param obj  Pointer to object to invoke member function on
-     *  @param func Member function to attach
-     */
-    template<typename T>
-    Callback(T *obj, R (T::*func)(A0, A1)) {
-        attach(obj, func);
-    }
-
-    /** Create a Callback with another Callback
-     *  @param func Callback to attach
-     */
-    Callback(const Callback<R(A0, A1)> &func) {
-        attach(func);
-    }
-
-    /** Attach a static function
-     *  @param func Static function to attach
-     */
-    void attach(R (*func)(A0, A1)) {
-        memcpy(&_func, &func, sizeof func);
-        _thunk = func ? &Callback::_staticthunk : 0;
-    }
-
-    /** Attach a static function with a bound pointer
-     *  @param obj  Pointer to object to bind to function
-     *  @param func Static function to attach
-     */
-    template <typename T>
-    void attach(T *obj, R (*func)(T*, A0, A1)) {
-        _obj = (void*)obj;
-        memcpy(&_func, &func, sizeof func);
-        _thunk = &Callback::_boundthunk<T>;
-    }
-
-    /** Attach a member function
-     *  @param obj  Pointer to object to invoke member function on
-     *  @param func Member function to attach
-     */
-    template<typename T>
-    void attach(T *obj, R (T::*func)(A0, A1)) {
-        _obj = static_cast<void*>(obj);
-        memcpy(&_func, &func, sizeof func);
-        _thunk = &Callback::_methodthunk<T>;
-    }
-
-    /** Attach a Callback
-     *  @param func The Callback to attach
-     */
-    void attach(const Callback<R(A0, A1)> &func) {
-        _obj = func._obj;
-        memcpy(&_func, &func._func, sizeof _func);
-        _thunk = func._thunk;
-    }
-
-    /** Call the attached function
-     */
-    R call(A0 a0, A1 a1) {
-        if (!_thunk) {
-            return (R)0;
-        }
-        return _thunk(_obj, &_func, a0, a1);
-    }
-
-    /** Call the attached function
-     */
-    R operator()(A0 a0, A1 a1) {
-        return call(a0, a1);
-    }
-
-    /** Test if function has been attached
-     */
-    operator bool() const {
-        return _thunk;
-    }
-
-    /** Static thunk for passing as C-style function
-     *  @param func Callback to call passed as void pointer
-     */
-    static R thunk(void *func, A0 a0, A1 a1) {
-        return static_cast<Callback<R(A0, A1)>*>(func)
-                ->call(a0, a1);
-    }
-
-private:
-    // Internal thunks for various function types
-    static R _staticthunk(void*, void *func, A0 a0, A1 a1) {
-        return (*reinterpret_cast<R (**)(A0, A1)>(func))
-                (a0, a1);
-    }
-
-    template<typename T>
-    static R _boundthunk(void *obj, void *func, A0 a0, A1 a1) {
-        return (*reinterpret_cast<R (**)(T*, A0, A1)>(func))
-                (static_cast<T*>(obj), a0, a1);
-    }
-
-    template<typename T>
-    static R _methodthunk(void *obj, void *func, A0 a0, A1 a1) {
-        return (static_cast<T*>(obj)->*
-                (*reinterpret_cast<R (T::**)(A0, A1)>(func)))
-                (a0, a1);
-    }
-
-    // Stored as pointer to function and pointer to optional object
-    // Function pointer is stored as union of possible function types
-    // to garuntee proper size and alignment
-    struct _class;
-    union {
-        void (*_staticfunc)();
-        void (*_boundfunc)(_class *);
-        void (_class::*_methodfunc)();
-    } _func;
-
-    void *_obj;
-
-    // Thunk registered on attach to dispatch calls
-    R (*_thunk)(void*, void*, A0, A1); 
-};
-
-/** Templated function class
- */
-template <typename R, typename A0>
-class Callback<R(A0)> {
-public:
-    /** Create a Callback with a static function
-     *  @param func Static function to attach
-     */
-    Callback(R (*func)(A0) = 0) {
-        attach(func);
-    }
-
-    /** Create a Callback with a static function and bound pointer
-     *  @param obj  Pointer to object to bind to function
-     *  @param func Static function to attach
-     */
-    template<typename T>
-    Callback(T *obj, R (*func)(T*, A0)) {
-        attach(obj, func);
-    }
-
-    /** Create a Callback with a member function
-     *  @param obj  Pointer to object to invoke member function on
-     *  @param func Member function to attach
-     */
-    template<typename T>
-    Callback(T *obj, R (T::*func)(A0)) {
-        attach(obj, func);
-    }
-
-    /** Create a Callback with another Callback
-     *  @param func Callback to attach
-     */
-    Callback(const Callback<R(A0)> &func) {
-        attach(func);
-    }
-
-    /** Attach a static function
-     *  @param func Static function to attach
-     */
-    void attach(R (*func)(A0)) {
-        memcpy(&_func, &func, sizeof func);
-        _thunk = func ? &Callback::_staticthunk : 0;
-    }
-
-    /** Attach a static function with a bound pointer
-     *  @param obj  Pointer to object to bind to function
-     *  @param func Static function to attach
-     */
-    template <typename T>
-    void attach(T *obj, R (*func)(T*, A0)) {
-        _obj = (void*)obj;
-        memcpy(&_func, &func, sizeof func);
-        _thunk = &Callback::_boundthunk<T>;
-    }
-
-    /** Attach a member function
-     *  @param obj  Pointer to object to invoke member function on
-     *  @param func Member function to attach
-     */
-    template<typename T>
-    void attach(T *obj, R (T::*func)(A0)) {
-        _obj = static_cast<void*>(obj);
-        memcpy(&_func, &func, sizeof func);
-        _thunk = &Callback::_methodthunk<T>;
-    }
-
-    /** Attach a Callback
-     *  @param func The Callback to attach
-     */
-    void attach(const Callback<R(A0)> &func) {
-        _obj = func._obj;
-        memcpy(&_func, &func._func, sizeof _func);
-        _thunk = func._thunk;
-    }
-
-    /** Call the attached function
-     */
-    R call(A0 a0) {
-        if (!_thunk) {
-            return (R)0;
-        }
-        return _thunk(_obj, &_func, a0);
-    }
-
-    /** Call the attached function
-     */
-    R operator()(A0 a0) {
-        return call(a0);
-    }
-
-    /** Test if function has been attached
-     */
-    operator bool() const {
-        return _thunk;
-    }
-
-    /** Static thunk for passing as C-style function
-     *  @param func Callback to call passed as void pointer
-     */
-    static R thunk(void *func, A0 a0) {
-        return static_cast<Callback<R(A0)>*>(func)
-                ->call(a0);
-    }
-
-private:
-    // Internal thunks for various function types
-    static R _staticthunk(void*, void *func, A0 a0) {
-        return (*reinterpret_cast<R (**)(A0)>(func))
-                (a0);
-    }
-
-    template<typename T>
-    static R _boundthunk(void *obj, void *func, A0 a0) {
-        return (*reinterpret_cast<R (**)(T*, A0)>(func))
-                (static_cast<T*>(obj), a0);
-    }
-
-    template<typename T>
-    static R _methodthunk(void *obj, void *func, A0 a0) {
-        return (static_cast<T*>(obj)->*
-                (*reinterpret_cast<R (T::**)(A0)>(func)))
-                (a0);
-    }
-
-    // Stored as pointer to function and pointer to optional object
-    // Function pointer is stored as union of possible function types
-    // to garuntee proper size and alignment
-    struct _class;
-    union {
-        void (*_staticfunc)();
-        void (*_boundfunc)(_class *);
-        void (_class::*_methodfunc)();
-    } _func;
-
-    void *_obj;
-
-    // Thunk registered on attach to dispatch calls
-    R (*_thunk)(void*, void*, A0); 
-};
-
 /** Templated function class
  */
 template <typename R>
@@ -746,6 +41,13 @@ public:
         attach(func);
     }
 
+    /** Create a Callback with another Callback
+     *  @param func Callback to attach
+     */
+    Callback(const Callback<R()> &func) {
+        attach(func);
+    }
+
     /** Create a Callback with a static function and bound pointer
      *  @param obj  Pointer to object to bind to function
      *  @param func Static function to attach
@@ -755,6 +57,21 @@ public:
         attach(obj, func);
     }
 
+    template<typename T>
+    Callback(const T *obj, R (*func)(const T*)) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(volatile T *obj, R (*func)(volatile T*)) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(const volatile T *obj, R (*func)(const volatile T*)) {
+        attach(obj, func);
+    }
+
     /** Create a Callback with a member function
      *  @param obj  Pointer to object to invoke member function on
      *  @param func Member function to attach
@@ -764,41 +81,34 @@ public:
         attach(obj, func);
     }
 
-    /** Create a Callback with another Callback
-     *  @param func Callback to attach
-     */
-    Callback(const Callback<R()> &func) {
-        attach(func);
+    template<typename T>
+    Callback(const T *obj, R (T::*func)() const) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(volatile T *obj, R (T::*func)() volatile) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(const volatile T *obj, R (T::*func)() const volatile) {
+        attach(obj, func);
     }
 
     /** Attach a static function
      *  @param func Static function to attach
      */
     void attach(R (*func)()) {
-        memcpy(&_func, &func, sizeof func);
-        _thunk = func ? &Callback::_staticthunk : 0;
-    }
+        struct local {
+            static R _thunk(void*, void *func) {
+                return (*(R (**)())func)(
+                        );
+            }
+        };
 
-    /** Attach a static function with a bound pointer
-     *  @param obj  Pointer to object to bind to function
-     *  @param func Static function to attach
-     */
-    template <typename T>
-    void attach(T *obj, R (*func)(T*)) {
-        _obj = (void*)obj;
         memcpy(&_func, &func, sizeof func);
-        _thunk = &Callback::_boundthunk<T>;
-    }
-
-    /** Attach a member function
-     *  @param obj  Pointer to object to invoke member function on
-     *  @param func Member function to attach
-     */
-    template<typename T>
-    void attach(T *obj, R (T::*func)()) {
-        _obj = static_cast<void*>(obj);
-        memcpy(&_func, &func, sizeof func);
-        _thunk = &Callback::_methodthunk<T>;
+        _thunk = func ? &local::_thunk : 0;
     }
 
     /** Attach a Callback
@@ -810,6 +120,126 @@ public:
         _thunk = func._thunk;
     }
 
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
+    template <typename T>
+    void attach(T *obj, R (*func)(T*)) {
+        struct local {
+            static R _thunk(void *obj, void *func) {
+                return (*(R (**)(T*))func)(
+                        (T*)obj);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template <typename T>
+    void attach(const T *obj, R (*func)(const T*)) {
+        struct local {
+            static R _thunk(void *obj, void *func) {
+                return (*(R (**)(const T*))func)(
+                        (const T*)obj);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template <typename T>
+    void attach(volatile T *obj, R (*func)(volatile T*)) {
+        struct local {
+            static R _thunk(void *obj, void *func) {
+                return (*(R (**)(volatile T*))func)(
+                        (volatile T*)obj);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template <typename T>
+    void attach(const volatile T *obj, R (*func)(const volatile T*)) {
+        struct local {
+            static R _thunk(void *obj, void *func) {
+                return (*(R (**)(const volatile T*))func)(
+                        (const volatile T*)obj);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    /** Attach a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
+    template<typename T>
+    void attach(T *obj, R (T::*func)()) {
+        struct local {
+            static R _thunk(void *obj, void *func) {
+                return (((T*)obj)->*(*(R (T::**)())func))(
+                        );
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template<typename T>
+    void attach(const T *obj, R (T::*func)() const) {
+        struct local {
+            static R _thunk(void *obj, void *func) {
+                return (((const T*)obj)->*(*(R (T::**)() const)func))(
+                        );
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template<typename T>
+    void attach(volatile T *obj, R (T::*func)() volatile) {
+        struct local {
+            static R _thunk(void *obj, void *func) {
+                return (((volatile T*)obj)->*(*(R (T::**)() volatile)func))(
+                        );
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template<typename T>
+    void attach(const volatile T *obj, R (T::*func)() const volatile) {
+        struct local {
+            static R _thunk(void *obj, void *func) {
+                return (((const volatile T*)obj)->*(*(R (T::**)() const volatile)func))(
+                        );
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
     /** Call the attached function
      */
     R call() {
@@ -835,30 +265,11 @@ public:
      *  @param func Callback to call passed as void pointer
      */
     static R thunk(void *func) {
-        return static_cast<Callback<R()>*>(func)
-                ->call();
+        return static_cast<Callback<R()>*>(func)->call(
+                );
     }
 
 private:
-    // Internal thunks for various function types
-    static R _staticthunk(void*, void *func) {
-        return (*reinterpret_cast<R (**)()>(func))
-                ();
-    }
-
-    template<typename T>
-    static R _boundthunk(void *obj, void *func) {
-        return (*reinterpret_cast<R (**)(T*)>(func))
-                (static_cast<T*>(obj));
-    }
-
-    template<typename T>
-    static R _methodthunk(void *obj, void *func) {
-        return (static_cast<T*>(obj)->*
-                (*reinterpret_cast<R (T::**)()>(func)))
-                ();
-    }
-
     // Stored as pointer to function and pointer to optional object
     // Function pointer is stored as union of possible function types
     // to garuntee proper size and alignment
@@ -872,10 +283,1596 @@ private:
     void *_obj;
 
     // Thunk registered on attach to dispatch calls
-    R (*_thunk)(void*, void*); 
+    R (*_thunk)(void*, void*);
 };
 
- typedef Callback<void(int)> event_callback_t;
+/** Templated function class
+ */
+template <typename R, typename A0>
+class Callback<R(A0)> {
+public:
+    /** Create a Callback with a static function
+     *  @param func Static function to attach
+     */
+    Callback(R (*func)(A0) = 0) {
+        attach(func);
+    }
+
+    /** Create a Callback with another Callback
+     *  @param func Callback to attach
+     */
+    Callback(const Callback<R(A0)> &func) {
+        attach(func);
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
+    template<typename T>
+    Callback(T *obj, R (*func)(T*, A0)) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(const T *obj, R (*func)(const T*, A0)) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(volatile T *obj, R (*func)(volatile T*, A0)) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(const volatile T *obj, R (*func)(const volatile T*, A0)) {
+        attach(obj, func);
+    }
+
+    /** Create a Callback with a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
+    template<typename T>
+    Callback(T *obj, R (T::*func)(A0)) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(const T *obj, R (T::*func)(A0) const) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(volatile T *obj, R (T::*func)(A0) volatile) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(const volatile T *obj, R (T::*func)(A0) const volatile) {
+        attach(obj, func);
+    }
+
+    /** Attach a static function
+     *  @param func Static function to attach
+     */
+    void attach(R (*func)(A0)) {
+        struct local {
+            static R _thunk(void*, void *func, A0 a0) {
+                return (*(R (**)(A0))func)(
+                        a0);
+            }
+        };
+
+        memcpy(&_func, &func, sizeof func);
+        _thunk = func ? &local::_thunk : 0;
+    }
+
+    /** Attach a Callback
+     *  @param func The Callback to attach
+     */
+    void attach(const Callback<R(A0)> &func) {
+        _obj = func._obj;
+        memcpy(&_func, &func._func, sizeof _func);
+        _thunk = func._thunk;
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
+    template <typename T>
+    void attach(T *obj, R (*func)(T*, A0)) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0) {
+                return (*(R (**)(T*, A0))func)(
+                        (T*)obj, a0);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template <typename T>
+    void attach(const T *obj, R (*func)(const T*, A0)) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0) {
+                return (*(R (**)(const T*, A0))func)(
+                        (const T*)obj, a0);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template <typename T>
+    void attach(volatile T *obj, R (*func)(volatile T*, A0)) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0) {
+                return (*(R (**)(volatile T*, A0))func)(
+                        (volatile T*)obj, a0);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template <typename T>
+    void attach(const volatile T *obj, R (*func)(const volatile T*, A0)) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0) {
+                return (*(R (**)(const volatile T*, A0))func)(
+                        (const volatile T*)obj, a0);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    /** Attach a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
+    template<typename T>
+    void attach(T *obj, R (T::*func)(A0)) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0) {
+                return (((T*)obj)->*(*(R (T::**)(A0))func))(
+                        a0);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template<typename T>
+    void attach(const T *obj, R (T::*func)(A0) const) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0) {
+                return (((const T*)obj)->*(*(R (T::**)(A0) const)func))(
+                        a0);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template<typename T>
+    void attach(volatile T *obj, R (T::*func)(A0) volatile) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0) {
+                return (((volatile T*)obj)->*(*(R (T::**)(A0) volatile)func))(
+                        a0);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template<typename T>
+    void attach(const volatile T *obj, R (T::*func)(A0) const volatile) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0) {
+                return (((const volatile T*)obj)->*(*(R (T::**)(A0) const volatile)func))(
+                        a0);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    /** Call the attached function
+     */
+    R call(A0 a0) {
+        if (!_thunk) {
+            return (R)0;
+        }
+        return _thunk(_obj, &_func, a0);
+    }
+
+    /** Call the attached function
+     */
+    R operator()(A0 a0) {
+        return call(a0);
+    }
+
+    /** Test if function has been attached
+     */
+    operator bool() const {
+        return _thunk;
+    }
+
+    /** Static thunk for passing as C-style function
+     *  @param func Callback to call passed as void pointer
+     */
+    static R thunk(void *func, A0 a0) {
+        return static_cast<Callback<R(A0)>*>(func)->call(
+                a0);
+    }
+
+private:
+    // Stored as pointer to function and pointer to optional object
+    // Function pointer is stored as union of possible function types
+    // to garuntee proper size and alignment
+    struct _class;
+    union {
+        void (*_staticfunc)();
+        void (*_boundfunc)(_class *);
+        void (_class::*_methodfunc)();
+    } _func;
+
+    void *_obj;
+
+    // Thunk registered on attach to dispatch calls
+    R (*_thunk)(void*, void*, A0);
+};
+
+/** Templated function class
+ */
+template <typename R, typename A0, typename A1>
+class Callback<R(A0, A1)> {
+public:
+    /** Create a Callback with a static function
+     *  @param func Static function to attach
+     */
+    Callback(R (*func)(A0, A1) = 0) {
+        attach(func);
+    }
+
+    /** Create a Callback with another Callback
+     *  @param func Callback to attach
+     */
+    Callback(const Callback<R(A0, A1)> &func) {
+        attach(func);
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
+    template<typename T>
+    Callback(T *obj, R (*func)(T*, A0, A1)) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(const T *obj, R (*func)(const T*, A0, A1)) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(volatile T *obj, R (*func)(volatile T*, A0, A1)) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(const volatile T *obj, R (*func)(const volatile T*, A0, A1)) {
+        attach(obj, func);
+    }
+
+    /** Create a Callback with a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
+    template<typename T>
+    Callback(T *obj, R (T::*func)(A0, A1)) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(const T *obj, R (T::*func)(A0, A1) const) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(volatile T *obj, R (T::*func)(A0, A1) volatile) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(const volatile T *obj, R (T::*func)(A0, A1) const volatile) {
+        attach(obj, func);
+    }
+
+    /** Attach a static function
+     *  @param func Static function to attach
+     */
+    void attach(R (*func)(A0, A1)) {
+        struct local {
+            static R _thunk(void*, void *func, A0 a0, A1 a1) {
+                return (*(R (**)(A0, A1))func)(
+                        a0, a1);
+            }
+        };
+
+        memcpy(&_func, &func, sizeof func);
+        _thunk = func ? &local::_thunk : 0;
+    }
+
+    /** Attach a Callback
+     *  @param func The Callback to attach
+     */
+    void attach(const Callback<R(A0, A1)> &func) {
+        _obj = func._obj;
+        memcpy(&_func, &func._func, sizeof _func);
+        _thunk = func._thunk;
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
+    template <typename T>
+    void attach(T *obj, R (*func)(T*, A0, A1)) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0, A1 a1) {
+                return (*(R (**)(T*, A0, A1))func)(
+                        (T*)obj, a0, a1);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template <typename T>
+    void attach(const T *obj, R (*func)(const T*, A0, A1)) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0, A1 a1) {
+                return (*(R (**)(const T*, A0, A1))func)(
+                        (const T*)obj, a0, a1);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template <typename T>
+    void attach(volatile T *obj, R (*func)(volatile T*, A0, A1)) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0, A1 a1) {
+                return (*(R (**)(volatile T*, A0, A1))func)(
+                        (volatile T*)obj, a0, a1);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template <typename T>
+    void attach(const volatile T *obj, R (*func)(const volatile T*, A0, A1)) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0, A1 a1) {
+                return (*(R (**)(const volatile T*, A0, A1))func)(
+                        (const volatile T*)obj, a0, a1);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    /** Attach a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
+    template<typename T>
+    void attach(T *obj, R (T::*func)(A0, A1)) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0, A1 a1) {
+                return (((T*)obj)->*(*(R (T::**)(A0, A1))func))(
+                        a0, a1);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template<typename T>
+    void attach(const T *obj, R (T::*func)(A0, A1) const) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0, A1 a1) {
+                return (((const T*)obj)->*(*(R (T::**)(A0, A1) const)func))(
+                        a0, a1);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template<typename T>
+    void attach(volatile T *obj, R (T::*func)(A0, A1) volatile) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0, A1 a1) {
+                return (((volatile T*)obj)->*(*(R (T::**)(A0, A1) volatile)func))(
+                        a0, a1);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template<typename T>
+    void attach(const volatile T *obj, R (T::*func)(A0, A1) const volatile) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0, A1 a1) {
+                return (((const volatile T*)obj)->*(*(R (T::**)(A0, A1) const volatile)func))(
+                        a0, a1);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    /** Call the attached function
+     */
+    R call(A0 a0, A1 a1) {
+        if (!_thunk) {
+            return (R)0;
+        }
+        return _thunk(_obj, &_func, a0, a1);
+    }
+
+    /** Call the attached function
+     */
+    R operator()(A0 a0, A1 a1) {
+        return call(a0, a1);
+    }
+
+    /** Test if function has been attached
+     */
+    operator bool() const {
+        return _thunk;
+    }
+
+    /** Static thunk for passing as C-style function
+     *  @param func Callback to call passed as void pointer
+     */
+    static R thunk(void *func, A0 a0, A1 a1) {
+        return static_cast<Callback<R(A0, A1)>*>(func)->call(
+                a0, a1);
+    }
+
+private:
+    // Stored as pointer to function and pointer to optional object
+    // Function pointer is stored as union of possible function types
+    // to garuntee proper size and alignment
+    struct _class;
+    union {
+        void (*_staticfunc)();
+        void (*_boundfunc)(_class *);
+        void (_class::*_methodfunc)();
+    } _func;
+
+    void *_obj;
+
+    // Thunk registered on attach to dispatch calls
+    R (*_thunk)(void*, void*, A0, A1);
+};
+
+/** Templated function class
+ */
+template <typename R, typename A0, typename A1, typename A2>
+class Callback<R(A0, A1, A2)> {
+public:
+    /** Create a Callback with a static function
+     *  @param func Static function to attach
+     */
+    Callback(R (*func)(A0, A1, A2) = 0) {
+        attach(func);
+    }
+
+    /** Create a Callback with another Callback
+     *  @param func Callback to attach
+     */
+    Callback(const Callback<R(A0, A1, A2)> &func) {
+        attach(func);
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
+    template<typename T>
+    Callback(T *obj, R (*func)(T*, A0, A1, A2)) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(const T *obj, R (*func)(const T*, A0, A1, A2)) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(volatile T *obj, R (*func)(volatile T*, A0, A1, A2)) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(const volatile T *obj, R (*func)(const volatile T*, A0, A1, A2)) {
+        attach(obj, func);
+    }
+
+    /** Create a Callback with a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
+    template<typename T>
+    Callback(T *obj, R (T::*func)(A0, A1, A2)) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(const T *obj, R (T::*func)(A0, A1, A2) const) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(volatile T *obj, R (T::*func)(A0, A1, A2) volatile) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(const volatile T *obj, R (T::*func)(A0, A1, A2) const volatile) {
+        attach(obj, func);
+    }
+
+    /** Attach a static function
+     *  @param func Static function to attach
+     */
+    void attach(R (*func)(A0, A1, A2)) {
+        struct local {
+            static R _thunk(void*, void *func, A0 a0, A1 a1, A2 a2) {
+                return (*(R (**)(A0, A1, A2))func)(
+                        a0, a1, a2);
+            }
+        };
+
+        memcpy(&_func, &func, sizeof func);
+        _thunk = func ? &local::_thunk : 0;
+    }
+
+    /** Attach a Callback
+     *  @param func The Callback to attach
+     */
+    void attach(const Callback<R(A0, A1, A2)> &func) {
+        _obj = func._obj;
+        memcpy(&_func, &func._func, sizeof _func);
+        _thunk = func._thunk;
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
+    template <typename T>
+    void attach(T *obj, R (*func)(T*, A0, A1, A2)) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2) {
+                return (*(R (**)(T*, A0, A1, A2))func)(
+                        (T*)obj, a0, a1, a2);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template <typename T>
+    void attach(const T *obj, R (*func)(const T*, A0, A1, A2)) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2) {
+                return (*(R (**)(const T*, A0, A1, A2))func)(
+                        (const T*)obj, a0, a1, a2);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template <typename T>
+    void attach(volatile T *obj, R (*func)(volatile T*, A0, A1, A2)) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2) {
+                return (*(R (**)(volatile T*, A0, A1, A2))func)(
+                        (volatile T*)obj, a0, a1, a2);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template <typename T>
+    void attach(const volatile T *obj, R (*func)(const volatile T*, A0, A1, A2)) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2) {
+                return (*(R (**)(const volatile T*, A0, A1, A2))func)(
+                        (const volatile T*)obj, a0, a1, a2);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    /** Attach a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
+    template<typename T>
+    void attach(T *obj, R (T::*func)(A0, A1, A2)) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2) {
+                return (((T*)obj)->*(*(R (T::**)(A0, A1, A2))func))(
+                        a0, a1, a2);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template<typename T>
+    void attach(const T *obj, R (T::*func)(A0, A1, A2) const) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2) {
+                return (((const T*)obj)->*(*(R (T::**)(A0, A1, A2) const)func))(
+                        a0, a1, a2);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template<typename T>
+    void attach(volatile T *obj, R (T::*func)(A0, A1, A2) volatile) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2) {
+                return (((volatile T*)obj)->*(*(R (T::**)(A0, A1, A2) volatile)func))(
+                        a0, a1, a2);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template<typename T>
+    void attach(const volatile T *obj, R (T::*func)(A0, A1, A2) const volatile) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2) {
+                return (((const volatile T*)obj)->*(*(R (T::**)(A0, A1, A2) const volatile)func))(
+                        a0, a1, a2);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    /** Call the attached function
+     */
+    R call(A0 a0, A1 a1, A2 a2) {
+        if (!_thunk) {
+            return (R)0;
+        }
+        return _thunk(_obj, &_func, a0, a1, a2);
+    }
+
+    /** Call the attached function
+     */
+    R operator()(A0 a0, A1 a1, A2 a2) {
+        return call(a0, a1, a2);
+    }
+
+    /** Test if function has been attached
+     */
+    operator bool() const {
+        return _thunk;
+    }
+
+    /** Static thunk for passing as C-style function
+     *  @param func Callback to call passed as void pointer
+     */
+    static R thunk(void *func, A0 a0, A1 a1, A2 a2) {
+        return static_cast<Callback<R(A0, A1, A2)>*>(func)->call(
+                a0, a1, a2);
+    }
+
+private:
+    // Stored as pointer to function and pointer to optional object
+    // Function pointer is stored as union of possible function types
+    // to garuntee proper size and alignment
+    struct _class;
+    union {
+        void (*_staticfunc)();
+        void (*_boundfunc)(_class *);
+        void (_class::*_methodfunc)();
+    } _func;
+
+    void *_obj;
+
+    // Thunk registered on attach to dispatch calls
+    R (*_thunk)(void*, void*, A0, A1, A2);
+};
+
+/** Templated function class
+ */
+template <typename R, typename A0, typename A1, typename A2, typename A3>
+class Callback<R(A0, A1, A2, A3)> {
+public:
+    /** Create a Callback with a static function
+     *  @param func Static function to attach
+     */
+    Callback(R (*func)(A0, A1, A2, A3) = 0) {
+        attach(func);
+    }
+
+    /** Create a Callback with another Callback
+     *  @param func Callback to attach
+     */
+    Callback(const Callback<R(A0, A1, A2, A3)> &func) {
+        attach(func);
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
+    template<typename T>
+    Callback(T *obj, R (*func)(T*, A0, A1, A2, A3)) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(const T *obj, R (*func)(const T*, A0, A1, A2, A3)) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(volatile T *obj, R (*func)(volatile T*, A0, A1, A2, A3)) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(const volatile T *obj, R (*func)(const volatile T*, A0, A1, A2, A3)) {
+        attach(obj, func);
+    }
+
+    /** Create a Callback with a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
+    template<typename T>
+    Callback(T *obj, R (T::*func)(A0, A1, A2, A3)) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(const T *obj, R (T::*func)(A0, A1, A2, A3) const) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(volatile T *obj, R (T::*func)(A0, A1, A2, A3) volatile) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(const volatile T *obj, R (T::*func)(A0, A1, A2, A3) const volatile) {
+        attach(obj, func);
+    }
+
+    /** Attach a static function
+     *  @param func Static function to attach
+     */
+    void attach(R (*func)(A0, A1, A2, A3)) {
+        struct local {
+            static R _thunk(void*, void *func, A0 a0, A1 a1, A2 a2, A3 a3) {
+                return (*(R (**)(A0, A1, A2, A3))func)(
+                        a0, a1, a2, a3);
+            }
+        };
+
+        memcpy(&_func, &func, sizeof func);
+        _thunk = func ? &local::_thunk : 0;
+    }
+
+    /** Attach a Callback
+     *  @param func The Callback to attach
+     */
+    void attach(const Callback<R(A0, A1, A2, A3)> &func) {
+        _obj = func._obj;
+        memcpy(&_func, &func._func, sizeof _func);
+        _thunk = func._thunk;
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
+    template <typename T>
+    void attach(T *obj, R (*func)(T*, A0, A1, A2, A3)) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3) {
+                return (*(R (**)(T*, A0, A1, A2, A3))func)(
+                        (T*)obj, a0, a1, a2, a3);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template <typename T>
+    void attach(const T *obj, R (*func)(const T*, A0, A1, A2, A3)) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3) {
+                return (*(R (**)(const T*, A0, A1, A2, A3))func)(
+                        (const T*)obj, a0, a1, a2, a3);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template <typename T>
+    void attach(volatile T *obj, R (*func)(volatile T*, A0, A1, A2, A3)) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3) {
+                return (*(R (**)(volatile T*, A0, A1, A2, A3))func)(
+                        (volatile T*)obj, a0, a1, a2, a3);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template <typename T>
+    void attach(const volatile T *obj, R (*func)(const volatile T*, A0, A1, A2, A3)) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3) {
+                return (*(R (**)(const volatile T*, A0, A1, A2, A3))func)(
+                        (const volatile T*)obj, a0, a1, a2, a3);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    /** Attach a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
+    template<typename T>
+    void attach(T *obj, R (T::*func)(A0, A1, A2, A3)) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3) {
+                return (((T*)obj)->*(*(R (T::**)(A0, A1, A2, A3))func))(
+                        a0, a1, a2, a3);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template<typename T>
+    void attach(const T *obj, R (T::*func)(A0, A1, A2, A3) const) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3) {
+                return (((const T*)obj)->*(*(R (T::**)(A0, A1, A2, A3) const)func))(
+                        a0, a1, a2, a3);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template<typename T>
+    void attach(volatile T *obj, R (T::*func)(A0, A1, A2, A3) volatile) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3) {
+                return (((volatile T*)obj)->*(*(R (T::**)(A0, A1, A2, A3) volatile)func))(
+                        a0, a1, a2, a3);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template<typename T>
+    void attach(const volatile T *obj, R (T::*func)(A0, A1, A2, A3) const volatile) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3) {
+                return (((const volatile T*)obj)->*(*(R (T::**)(A0, A1, A2, A3) const volatile)func))(
+                        a0, a1, a2, a3);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    /** Call the attached function
+     */
+    R call(A0 a0, A1 a1, A2 a2, A3 a3) {
+        if (!_thunk) {
+            return (R)0;
+        }
+        return _thunk(_obj, &_func, a0, a1, a2, a3);
+    }
+
+    /** Call the attached function
+     */
+    R operator()(A0 a0, A1 a1, A2 a2, A3 a3) {
+        return call(a0, a1, a2, a3);
+    }
+
+    /** Test if function has been attached
+     */
+    operator bool() const {
+        return _thunk;
+    }
+
+    /** Static thunk for passing as C-style function
+     *  @param func Callback to call passed as void pointer
+     */
+    static R thunk(void *func, A0 a0, A1 a1, A2 a2, A3 a3) {
+        return static_cast<Callback<R(A0, A1, A2, A3)>*>(func)->call(
+                a0, a1, a2, a3);
+    }
+
+private:
+    // Stored as pointer to function and pointer to optional object
+    // Function pointer is stored as union of possible function types
+    // to garuntee proper size and alignment
+    struct _class;
+    union {
+        void (*_staticfunc)();
+        void (*_boundfunc)(_class *);
+        void (_class::*_methodfunc)();
+    } _func;
+
+    void *_obj;
+
+    // Thunk registered on attach to dispatch calls
+    R (*_thunk)(void*, void*, A0, A1, A2, A3);
+};
+
+/** Templated function class
+ */
+template <typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
+class Callback<R(A0, A1, A2, A3, A4)> {
+public:
+    /** Create a Callback with a static function
+     *  @param func Static function to attach
+     */
+    Callback(R (*func)(A0, A1, A2, A3, A4) = 0) {
+        attach(func);
+    }
+
+    /** Create a Callback with another Callback
+     *  @param func Callback to attach
+     */
+    Callback(const Callback<R(A0, A1, A2, A3, A4)> &func) {
+        attach(func);
+    }
+
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
+    template<typename T>
+    Callback(T *obj, R (*func)(T*, A0, A1, A2, A3, A4)) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(const T *obj, R (*func)(const T*, A0, A1, A2, A3, A4)) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(volatile T *obj, R (*func)(volatile T*, A0, A1, A2, A3, A4)) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(const volatile T *obj, R (*func)(const volatile T*, A0, A1, A2, A3, A4)) {
+        attach(obj, func);
+    }
+
+    /** Create a Callback with a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
+    template<typename T>
+    Callback(T *obj, R (T::*func)(A0, A1, A2, A3, A4)) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(const T *obj, R (T::*func)(A0, A1, A2, A3, A4) const) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(volatile T *obj, R (T::*func)(A0, A1, A2, A3, A4) volatile) {
+        attach(obj, func);
+    }
+
+    template<typename T>
+    Callback(const volatile T *obj, R (T::*func)(A0, A1, A2, A3, A4) const volatile) {
+        attach(obj, func);
+    }
+
+    /** Attach a static function
+     *  @param func Static function to attach
+     */
+    void attach(R (*func)(A0, A1, A2, A3, A4)) {
+        struct local {
+            static R _thunk(void*, void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
+                return (*(R (**)(A0, A1, A2, A3, A4))func)(
+                        a0, a1, a2, a3, a4);
+            }
+        };
+
+        memcpy(&_func, &func, sizeof func);
+        _thunk = func ? &local::_thunk : 0;
+    }
+
+    /** Attach a Callback
+     *  @param func The Callback to attach
+     */
+    void attach(const Callback<R(A0, A1, A2, A3, A4)> &func) {
+        _obj = func._obj;
+        memcpy(&_func, &func._func, sizeof _func);
+        _thunk = func._thunk;
+    }
+
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
+    template <typename T>
+    void attach(T *obj, R (*func)(T*, A0, A1, A2, A3, A4)) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
+                return (*(R (**)(T*, A0, A1, A2, A3, A4))func)(
+                        (T*)obj, a0, a1, a2, a3, a4);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template <typename T>
+    void attach(const T *obj, R (*func)(const T*, A0, A1, A2, A3, A4)) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
+                return (*(R (**)(const T*, A0, A1, A2, A3, A4))func)(
+                        (const T*)obj, a0, a1, a2, a3, a4);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template <typename T>
+    void attach(volatile T *obj, R (*func)(volatile T*, A0, A1, A2, A3, A4)) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
+                return (*(R (**)(volatile T*, A0, A1, A2, A3, A4))func)(
+                        (volatile T*)obj, a0, a1, a2, a3, a4);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template <typename T>
+    void attach(const volatile T *obj, R (*func)(const volatile T*, A0, A1, A2, A3, A4)) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
+                return (*(R (**)(const volatile T*, A0, A1, A2, A3, A4))func)(
+                        (const volatile T*)obj, a0, a1, a2, a3, a4);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    /** Attach a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
+    template<typename T>
+    void attach(T *obj, R (T::*func)(A0, A1, A2, A3, A4)) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
+                return (((T*)obj)->*(*(R (T::**)(A0, A1, A2, A3, A4))func))(
+                        a0, a1, a2, a3, a4);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template<typename T>
+    void attach(const T *obj, R (T::*func)(A0, A1, A2, A3, A4) const) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
+                return (((const T*)obj)->*(*(R (T::**)(A0, A1, A2, A3, A4) const)func))(
+                        a0, a1, a2, a3, a4);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template<typename T>
+    void attach(volatile T *obj, R (T::*func)(A0, A1, A2, A3, A4) volatile) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
+                return (((volatile T*)obj)->*(*(R (T::**)(A0, A1, A2, A3, A4) volatile)func))(
+                        a0, a1, a2, a3, a4);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    template<typename T>
+    void attach(const volatile T *obj, R (T::*func)(A0, A1, A2, A3, A4) const volatile) {
+        struct local {
+            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
+                return (((const volatile T*)obj)->*(*(R (T::**)(A0, A1, A2, A3, A4) const volatile)func))(
+                        a0, a1, a2, a3, a4);
+            }
+        };
+
+        _obj = (void*)obj;
+        memcpy(&_func, &func, sizeof func);
+        _thunk = &local::_thunk;
+    }
+
+    /** Call the attached function
+     */
+    R call(A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
+        if (!_thunk) {
+            return (R)0;
+        }
+        return _thunk(_obj, &_func, a0, a1, a2, a3, a4);
+    }
+
+    /** Call the attached function
+     */
+    R operator()(A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
+        return call(a0, a1, a2, a3, a4);
+    }
+
+    /** Test if function has been attached
+     */
+    operator bool() const {
+        return _thunk;
+    }
+
+    /** Static thunk for passing as C-style function
+     *  @param func Callback to call passed as void pointer
+     */
+    static R thunk(void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
+        return static_cast<Callback<R(A0, A1, A2, A3, A4)>*>(func)->call(
+                a0, a1, a2, a3, a4);
+    }
+
+private:
+    // Stored as pointer to function and pointer to optional object
+    // Function pointer is stored as union of possible function types
+    // to garuntee proper size and alignment
+    struct _class;
+    union {
+        void (*_staticfunc)();
+        void (*_boundfunc)(_class *);
+        void (_class::*_methodfunc)();
+    } _func;
+
+    void *_obj;
+
+    // Thunk registered on attach to dispatch calls
+    R (*_thunk)(void*, void*, A0, A1, A2, A3, A4);
+};
+
+typedef Callback<void(int)> event_callback_t;
+
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with type infered from arguments
+ */
+template <typename R>
+Callback<R()> callback(R (*func)() = 0) {
+    return Callback<R()>(func);
+}
+
+template <typename R>
+Callback<R()> callback(const Callback<R()> &func) {
+    return Callback<R()>(func);
+}
+template <typename T, typename R>
+Callback<R()> callback(T *obj, R (*func)(T*)) {
+    return Callback<R()>(obj, func);
+}
+
+template <typename T, typename R>
+Callback<R()> callback(const T *obj, R (*func)(const T*)) {
+    return Callback<R()>(obj, func);
+}
+
+template <typename T, typename R>
+Callback<R()> callback(volatile T *obj, R (*func)(volatile T*)) {
+    return Callback<R()>(obj, func);
+}
+
+template <typename T, typename R>
+Callback<R()> callback(const volatile T *obj, R (*func)(const volatile T*)) {
+    return Callback<R()>(obj, func);
+}
+
+template<typename T, typename R>
+Callback<R()> callback(T *obj, R (T::*func)()) {
+    return Callback<R()>(obj, func);
+}
+
+template<typename T, typename R>
+Callback<R()> callback(const T *obj, R (T::*func)() const) {
+    return Callback<R()>(obj, func);
+}
+
+template<typename T, typename R>
+Callback<R()> callback(volatile T *obj, R (T::*func)() volatile) {
+    return Callback<R()>(obj, func);
+}
+
+template<typename T, typename R>
+Callback<R()> callback(const volatile T *obj, R (T::*func)() const volatile) {
+    return Callback<R()>(obj, func);
+}
+
+template <typename R, typename A0>
+Callback<R(A0)> callback(R (*func)(A0) = 0) {
+    return Callback<R(A0)>(func);
+}
+
+template <typename R, typename A0>
+Callback<R(A0)> callback(const Callback<R(A0)> &func) {
+    return Callback<R(A0)>(func);
+}
+template <typename T, typename R, typename A0>
+Callback<R(A0)> callback(T *obj, R (*func)(T*, A0)) {
+    return Callback<R(A0)>(obj, func);
+}
+
+template <typename T, typename R, typename A0>
+Callback<R(A0)> callback(const T *obj, R (*func)(const T*, A0)) {
+    return Callback<R(A0)>(obj, func);
+}
+
+template <typename T, typename R, typename A0>
+Callback<R(A0)> callback(volatile T *obj, R (*func)(volatile T*, A0)) {
+    return Callback<R(A0)>(obj, func);
+}
+
+template <typename T, typename R, typename A0>
+Callback<R(A0)> callback(const volatile T *obj, R (*func)(const volatile T*, A0)) {
+    return Callback<R(A0)>(obj, func);
+}
+
+template<typename T, typename R, typename A0>
+Callback<R(A0)> callback(T *obj, R (T::*func)(A0)) {
+    return Callback<R(A0)>(obj, func);
+}
+
+template<typename T, typename R, typename A0>
+Callback<R(A0)> callback(const T *obj, R (T::*func)(A0) const) {
+    return Callback<R(A0)>(obj, func);
+}
+
+template<typename T, typename R, typename A0>
+Callback<R(A0)> callback(volatile T *obj, R (T::*func)(A0) volatile) {
+    return Callback<R(A0)>(obj, func);
+}
+
+template<typename T, typename R, typename A0>
+Callback<R(A0)> callback(const volatile T *obj, R (T::*func)(A0) const volatile) {
+    return Callback<R(A0)>(obj, func);
+}
+
+template <typename R, typename A0, typename A1>
+Callback<R(A0, A1)> callback(R (*func)(A0, A1) = 0) {
+    return Callback<R(A0, A1)>(func);
+}
+
+template <typename R, typename A0, typename A1>
+Callback<R(A0, A1)> callback(const Callback<R(A0, A1)> &func) {
+    return Callback<R(A0, A1)>(func);
+}
+template <typename T, typename R, typename A0, typename A1>
+Callback<R(A0, A1)> callback(T *obj, R (*func)(T*, A0, A1)) {
+    return Callback<R(A0, A1)>(obj, func);
+}
+
+template <typename T, typename R, typename A0, typename A1>
+Callback<R(A0, A1)> callback(const T *obj, R (*func)(const T*, A0, A1)) {
+    return Callback<R(A0, A1)>(obj, func);
+}
+
+template <typename T, typename R, typename A0, typename A1>
+Callback<R(A0, A1)> callback(volatile T *obj, R (*func)(volatile T*, A0, A1)) {
+    return Callback<R(A0, A1)>(obj, func);
+}
+
+template <typename T, typename R, typename A0, typename A1>
+Callback<R(A0, A1)> callback(const volatile T *obj, R (*func)(const volatile T*, A0, A1)) {
+    return Callback<R(A0, A1)>(obj, func);
+}
+
+template<typename T, typename R, typename A0, typename A1>
+Callback<R(A0, A1)> callback(T *obj, R (T::*func)(A0, A1)) {
+    return Callback<R(A0, A1)>(obj, func);
+}
+
+template<typename T, typename R, typename A0, typename A1>
+Callback<R(A0, A1)> callback(const T *obj, R (T::*func)(A0, A1) const) {
+    return Callback<R(A0, A1)>(obj, func);
+}
+
+template<typename T, typename R, typename A0, typename A1>
+Callback<R(A0, A1)> callback(volatile T *obj, R (T::*func)(A0, A1) volatile) {
+    return Callback<R(A0, A1)>(obj, func);
+}
+
+template<typename T, typename R, typename A0, typename A1>
+Callback<R(A0, A1)> callback(const volatile T *obj, R (T::*func)(A0, A1) const volatile) {
+    return Callback<R(A0, A1)>(obj, func);
+}
+
+template <typename R, typename A0, typename A1, typename A2>
+Callback<R(A0, A1, A2)> callback(R (*func)(A0, A1, A2) = 0) {
+    return Callback<R(A0, A1, A2)>(func);
+}
+
+template <typename R, typename A0, typename A1, typename A2>
+Callback<R(A0, A1, A2)> callback(const Callback<R(A0, A1, A2)> &func) {
+    return Callback<R(A0, A1, A2)>(func);
+}
+template <typename T, typename R, typename A0, typename A1, typename A2>
+Callback<R(A0, A1, A2)> callback(T *obj, R (*func)(T*, A0, A1, A2)) {
+    return Callback<R(A0, A1, A2)>(obj, func);
+}
+
+template <typename T, typename R, typename A0, typename A1, typename A2>
+Callback<R(A0, A1, A2)> callback(const T *obj, R (*func)(const T*, A0, A1, A2)) {
+    return Callback<R(A0, A1, A2)>(obj, func);
+}
+
+template <typename T, typename R, typename A0, typename A1, typename A2>
+Callback<R(A0, A1, A2)> callback(volatile T *obj, R (*func)(volatile T*, A0, A1, A2)) {
+    return Callback<R(A0, A1, A2)>(obj, func);
+}
+
+template <typename T, typename R, typename A0, typename A1, typename A2>
+Callback<R(A0, A1, A2)> callback(const volatile T *obj, R (*func)(const volatile T*, A0, A1, A2)) {
+    return Callback<R(A0, A1, A2)>(obj, func);
+}
+
+template<typename T, typename R, typename A0, typename A1, typename A2>
+Callback<R(A0, A1, A2)> callback(T *obj, R (T::*func)(A0, A1, A2)) {
+    return Callback<R(A0, A1, A2)>(obj, func);
+}
+
+template<typename T, typename R, typename A0, typename A1, typename A2>
+Callback<R(A0, A1, A2)> callback(const T *obj, R (T::*func)(A0, A1, A2) const) {
+    return Callback<R(A0, A1, A2)>(obj, func);
+}
+
+template<typename T, typename R, typename A0, typename A1, typename A2>
+Callback<R(A0, A1, A2)> callback(volatile T *obj, R (T::*func)(A0, A1, A2) volatile) {
+    return Callback<R(A0, A1, A2)>(obj, func);
+}
+
+template<typename T, typename R, typename A0, typename A1, typename A2>
+Callback<R(A0, A1, A2)> callback(const volatile T *obj, R (T::*func)(A0, A1, A2) const volatile) {
+    return Callback<R(A0, A1, A2)>(obj, func);
+}
+
+template <typename R, typename A0, typename A1, typename A2, typename A3>
+Callback<R(A0, A1, A2, A3)> callback(R (*func)(A0, A1, A2, A3) = 0) {
+    return Callback<R(A0, A1, A2, A3)>(func);
+}
+
+template <typename R, typename A0, typename A1, typename A2, typename A3>
+Callback<R(A0, A1, A2, A3)> callback(const Callback<R(A0, A1, A2, A3)> &func) {
+    return Callback<R(A0, A1, A2, A3)>(func);
+}
+template <typename T, typename R, typename A0, typename A1, typename A2, typename A3>
+Callback<R(A0, A1, A2, A3)> callback(T *obj, R (*func)(T*, A0, A1, A2, A3)) {
+    return Callback<R(A0, A1, A2, A3)>(obj, func);
+}
+
+template <typename T, typename R, typename A0, typename A1, typename A2, typename A3>
+Callback<R(A0, A1, A2, A3)> callback(const T *obj, R (*func)(const T*, A0, A1, A2, A3)) {
+    return Callback<R(A0, A1, A2, A3)>(obj, func);
+}
+
+template <typename T, typename R, typename A0, typename A1, typename A2, typename A3>
+Callback<R(A0, A1, A2, A3)> callback(volatile T *obj, R (*func)(volatile T*, A0, A1, A2, A3)) {
+    return Callback<R(A0, A1, A2, A3)>(obj, func);
+}
+
+template <typename T, typename R, typename A0, typename A1, typename A2, typename A3>
+Callback<R(A0, A1, A2, A3)> callback(const volatile T *obj, R (*func)(const volatile T*, A0, A1, A2, A3)) {
+    return Callback<R(A0, A1, A2, A3)>(obj, func);
+}
+
+template<typename T, typename R, typename A0, typename A1, typename A2, typename A3>
+Callback<R(A0, A1, A2, A3)> callback(T *obj, R (T::*func)(A0, A1, A2, A3)) {
+    return Callback<R(A0, A1, A2, A3)>(obj, func);
+}
+
+template<typename T, typename R, typename A0, typename A1, typename A2, typename A3>
+Callback<R(A0, A1, A2, A3)> callback(const T *obj, R (T::*func)(A0, A1, A2, A3) const) {
+    return Callback<R(A0, A1, A2, A3)>(obj, func);
+}
+
+template<typename T, typename R, typename A0, typename A1, typename A2, typename A3>
+Callback<R(A0, A1, A2, A3)> callback(volatile T *obj, R (T::*func)(A0, A1, A2, A3) volatile) {
+    return Callback<R(A0, A1, A2, A3)>(obj, func);
+}
+
+template<typename T, typename R, typename A0, typename A1, typename A2, typename A3>
+Callback<R(A0, A1, A2, A3)> callback(const volatile T *obj, R (T::*func)(A0, A1, A2, A3) const volatile) {
+    return Callback<R(A0, A1, A2, A3)>(obj, func);
+}
+
+template <typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
+Callback<R(A0, A1, A2, A3, A4)> callback(R (*func)(A0, A1, A2, A3, A4) = 0) {
+    return Callback<R(A0, A1, A2, A3, A4)>(func);
+}
+
+template <typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
+Callback<R(A0, A1, A2, A3, A4)> callback(const Callback<R(A0, A1, A2, A3, A4)> &func) {
+    return Callback<R(A0, A1, A2, A3, A4)>(func);
+}
+template <typename T, typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
+Callback<R(A0, A1, A2, A3, A4)> callback(T *obj, R (*func)(T*, A0, A1, A2, A3, A4)) {
+    return Callback<R(A0, A1, A2, A3, A4)>(obj, func);
+}
+
+template <typename T, typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
+Callback<R(A0, A1, A2, A3, A4)> callback(const T *obj, R (*func)(const T*, A0, A1, A2, A3, A4)) {
+    return Callback<R(A0, A1, A2, A3, A4)>(obj, func);
+}
+
+template <typename T, typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
+Callback<R(A0, A1, A2, A3, A4)> callback(volatile T *obj, R (*func)(volatile T*, A0, A1, A2, A3, A4)) {
+    return Callback<R(A0, A1, A2, A3, A4)>(obj, func);
+}
+
+template <typename T, typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
+Callback<R(A0, A1, A2, A3, A4)> callback(const volatile T *obj, R (*func)(const volatile T*, A0, A1, A2, A3, A4)) {
+    return Callback<R(A0, A1, A2, A3, A4)>(obj, func);
+}
+
+template<typename T, typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
+Callback<R(A0, A1, A2, A3, A4)> callback(T *obj, R (T::*func)(A0, A1, A2, A3, A4)) {
+    return Callback<R(A0, A1, A2, A3, A4)>(obj, func);
+}
+
+template<typename T, typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
+Callback<R(A0, A1, A2, A3, A4)> callback(const T *obj, R (T::*func)(A0, A1, A2, A3, A4) const) {
+    return Callback<R(A0, A1, A2, A3, A4)>(obj, func);
+}
+
+template<typename T, typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
+Callback<R(A0, A1, A2, A3, A4)> callback(volatile T *obj, R (T::*func)(A0, A1, A2, A3, A4) volatile) {
+    return Callback<R(A0, A1, A2, A3, A4)>(obj, func);
+}
+
+template<typename T, typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
+Callback<R(A0, A1, A2, A3, A4)> callback(const volatile T *obj, R (T::*func)(A0, A1, A2, A3, A4) const volatile) {
+    return Callback<R(A0, A1, A2, A3, A4)>(obj, func);
+}
 
 
 } // namespace mbed
diff --git a/hal/api/InterruptIn.h b/hal/api/InterruptIn.h
index 3758ab5ca3..fcb7df4b81 100644
--- a/hal/api/InterruptIn.h
+++ b/hal/api/InterruptIn.h
@@ -24,6 +24,7 @@
 #include "gpio_irq_api.h"
 #include "Callback.h"
 #include "critical.h"
+#include "toolchain.h"
 
 namespace mbed {
 
@@ -88,11 +89,17 @@ public:
      *
      *  @param obj pointer to the object to call the member function on
      *  @param method pointer to the member function to be called
+     *  @deprecated
+     *      The rise function does not support cv-qualifiers. Replaced by
+     *      rise(callback(obj, method)).
      */
     template<typename T, typename M>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+        "The rise function does not support cv-qualifiers. Replaced by "
+        "rise(callback(obj, method)).")
     void rise(T *obj, M method) {
         core_util_critical_section_enter();
-        rise(Callback<void()>(obj, method));
+        rise(callback(obj, method));
         core_util_critical_section_exit();
     }
 
@@ -106,11 +113,17 @@ public:
      *
      *  @param obj pointer to the object to call the member function on
      *  @param method pointer to the member function to be called
+     *  @deprecated
+     *      The rise function does not support cv-qualifiers. Replaced by
+     *      rise(callback(obj, method)).
      */
     template<typename T, typename M>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+        "The fall function does not support cv-qualifiers. Replaced by "
+        "fall(callback(obj, method)).")
     void fall(T *obj, M method) {
         core_util_critical_section_enter();
-        fall(Callback<void()>(obj, method));
+        fall(callback(obj, method));
         core_util_critical_section_exit();
     }
 
diff --git a/hal/api/SerialBase.h b/hal/api/SerialBase.h
index 1d7ae7c34d..be79293095 100644
--- a/hal/api/SerialBase.h
+++ b/hal/api/SerialBase.h
@@ -23,6 +23,7 @@
 #include "Stream.h"
 #include "Callback.h"
 #include "serial_api.h"
+#include "toolchain.h"
 
 #if DEVICE_SERIAL_ASYNCH
 #include "CThunk.h"
@@ -101,10 +102,16 @@ public:
      *  @param obj pointer to the object to call the member function on
      *  @param method pointer to the member function to be called
      *  @param type Which serial interrupt to attach the member function to (Seriall::RxIrq for receive, TxIrq for transmit buffer empty)
+     *  @deprecated
+     *      The attach function does not support cv-qualifiers. Replaced by
+     *      attach(callback(obj, method), type).
      */
     template<typename T>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+        "The attach function does not support cv-qualifiers. Replaced by "
+        "attach(callback(obj, method), type).")
     void attach(T *obj, void (T::*method)(), IrqType type=RxIrq) {
-        attach(Callback<void()>(obj, method), type);
+        attach(callback(obj, method), type);
     }
 
     /** Attach a member function to call whenever a serial interrupt is generated
@@ -112,10 +119,16 @@ public:
      *  @param obj pointer to the object to call the member function on
      *  @param method pointer to the member function to be called
      *  @param type Which serial interrupt to attach the member function to (Seriall::RxIrq for receive, TxIrq for transmit buffer empty)
+     *  @deprecated
+     *      The attach function does not support cv-qualifiers. Replaced by
+     *      attach(callback(obj, method), type).
      */
     template<typename T>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+        "The attach function does not support cv-qualifiers. Replaced by "
+        "attach(callback(obj, method), type).")
     void attach(T *obj, void (*method)(T*), IrqType type=RxIrq) {
-        attach(Callback<void()>(obj, method), type);
+        attach(callback(obj, method), type);
     }
 
     /** Generate a break condition on the serial line
diff --git a/hal/api/Ticker.h b/hal/api/Ticker.h
index a7848ece4d..5b2f97ba95 100644
--- a/hal/api/Ticker.h
+++ b/hal/api/Ticker.h
@@ -18,6 +18,7 @@
 
 #include "TimerEvent.h"
 #include "Callback.h"
+#include "toolchain.h"
 
 namespace mbed {
 
@@ -80,10 +81,16 @@ public:
      *  @param obj pointer to the object to call the member function on
      *  @param method pointer to the member function to be called
      *  @param t the time between calls in seconds
+     *  @deprecated
+     *      The attach function does not support cv-qualifiers. Replaced by
+     *      attach(callback(obj, method), t).
      */
     template<typename T, typename M>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+        "The attach function does not support cv-qualifiers. Replaced by "
+        "attach(callback(obj, method), t).")
     void attach(T *obj, M method, float t) {
-        attach(Callback<void()>(obj, method), t);
+        attach(callback(obj, method), t);
     }
 
     /** Attach a function to be called by the Ticker, specifiying the interval in micro-seconds
@@ -101,8 +108,14 @@ public:
      *  @param tptr pointer to the object to call the member function on
      *  @param mptr pointer to the member function to be called
      *  @param t the time between calls in micro-seconds
+     *  @deprecated
+     *      The attach_us function does not support cv-qualifiers. Replaced by
+     *      attach_us(callback(obj, method), t).
      */
     template<typename T, typename M>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+        "The attach_us function does not support cv-qualifiers. Replaced by "
+        "attach_us(callback(obj, method), t).")
     void attach_us(T *obj, M method, timestamp_t t) {
         attach_us(Callback<void()>(obj, method), t);
     }
diff --git a/rtos/rtos/RtosTimer.h b/rtos/rtos/RtosTimer.h
index ab698ebd36..3f39a3999a 100644
--- a/rtos/rtos/RtosTimer.h
+++ b/rtos/rtos/RtosTimer.h
@@ -47,7 +47,7 @@ public:
     MBED_DEPRECATED_SINCE("mbed-os-5.1",
         "Replaced with RtosTimer(Callback<void()>, os_timer_type)")
     RtosTimer(void (*func)(void const *argument), os_timer_type type=osTimerPeriodic, void *argument=NULL) {
-        constructor(mbed::Callback<void()>(argument, (void (*)(void *))func), type);
+        constructor(mbed::callback(argument, (void (*)(void *))func), type);
     }
     
     /** Create timer.
@@ -62,10 +62,16 @@ public:
       @param   obj       pointer to the object to call the member function on.
       @param   method    member function to be executed by this timer.
       @param   type      osTimerOnce for one-shot or osTimerPeriodic for periodic behaviour. (default: osTimerPeriodic)
+      @deprecated
+          The RtosTimer constructor does not support cv-qualifiers. Replaced by
+          RtosTimer(callback(obj, method), os_timer_type).
     */
     template <typename T, typename M>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+        "The RtosTimer constructor does not support cv-qualifiers. Replaced by "
+        "RtosTimer(callback(obj, method), os_timer_type).")
     RtosTimer(T *obj, M method, os_timer_type type=osTimerPeriodic) {
-        constructor(mbed::Callback<void()>(obj, method), type);
+        constructor(mbed::callback(obj, method), type);
     }
 
     /** Stop the timer.
diff --git a/rtos/rtos/Thread.h b/rtos/rtos/Thread.h
index eb1c39beab..9d3356a607 100644
--- a/rtos/rtos/Thread.h
+++ b/rtos/rtos/Thread.h
@@ -90,7 +90,7 @@ public:
            osPriority priority=osPriorityNormal,
            uint32_t stack_size=DEFAULT_STACK_SIZE,
            unsigned char *stack_pointer=NULL) {
-        constructor(mbed::Callback<void()>(obj, method),
+        constructor(mbed::callback(obj, method),
                     priority, stack_size, stack_pointer);
     }
 
@@ -116,7 +116,7 @@ public:
            osPriority priority=osPriorityNormal,
            uint32_t stack_size=DEFAULT_STACK_SIZE,
            unsigned char *stack_pointer=NULL) {
-        constructor(mbed::Callback<void()>(obj, method),
+        constructor(mbed::callback(obj, method),
                     priority, stack_size, stack_pointer);
     }
 
@@ -141,7 +141,7 @@ public:
            osPriority priority=osPriorityNormal,
            uint32_t stack_size=DEFAULT_STACK_SIZE,
            unsigned char *stack_pointer=NULL) {
-        constructor(mbed::Callback<void()>(argument, (void (*)(void *))task),
+        constructor(mbed::callback(argument, (void (*)(void *))task),
                     priority, stack_size, stack_pointer);
     }
 
@@ -155,10 +155,16 @@ public:
       @param   obj            argument to task
       @param   method         function to be executed by this thread.
       @return  status code that indicates the execution status of the function.
+      @deprecated
+          The start function does not support cv-qualifiers. Replaced by
+          start(callback(obj, method)).
     */
     template <typename T, typename M>
+    MBED_DEPRECATED_SINCE("mbed-os-5.1",
+        "The start function does not support cv-qualifiers. Replaced by "
+        "start(callback(obj, method)).")
     osStatus start(T *obj, M method) {
-        return start(mbed::Callback<void()>(obj, method));
+        return start(mbed::callback(obj, method));
     }
 
     /** Wait for thread to terminate

From c71e67f2dcf2a75c225fbecf16921949100ca6c9 Mon Sep 17 00:00:00 2001
From: Christopher Haster <chaster@utexas.edu>
Date: Fri, 19 Aug 2016 15:49:49 -0500
Subject: [PATCH 2/3] Updated minor functionality of the Callback class

- Marked `call` and `operator()` functions as const
- Moved to static_cast for internal function pointer to avoid losing
  compiler checked const-safety
- Added test for `operator=` with non-callback types
- Moved from zero-cast to value-initializer when callback is null
- Added `operator==` and `operator!=`
- Removed special handling of null callback
- Replicated doxygen to all overloads
- Added correct nops where uninitialized callbacks are called
- Added assertion for null callback
- Removed copy-constructor from callback constructor
---
 TESTS/mbed_drivers/callback/main.cpp |  120 +--
 hal/api/Callback.h                   | 1259 +++++++++++++++++++++-----
 hal/api/FunctionPointer.h            |   24 +
 hal/common/CAN.cpp                   |    8 +
 hal/common/InterruptIn.cpp           |   10 +-
 hal/common/SerialBase.cpp            |    7 +
 6 files changed, 1100 insertions(+), 328 deletions(-)

diff --git a/TESTS/mbed_drivers/callback/main.cpp b/TESTS/mbed_drivers/callback/main.cpp
index d4f0e9af57..403968a039 100644
--- a/TESTS/mbed_drivers/callback/main.cpp
+++ b/TESTS/mbed_drivers/callback/main.cpp
@@ -203,20 +203,14 @@ void test_dispatch0() {
     Verifier<T>::verify0((volatile Thing<T>*)&thing, &volatile_func0<T>);
     Verifier<T>::verify0((const volatile Thing<T>*)&thing, &const_volatile_func0<T>);
     Verifier<T>::verify0(callback(static_func0<T>));
-    Verifier<T>::verify0(callback(&thing, &Thing<T>::member_func0));
-    Verifier<T>::verify0(callback((const Thing<T>*)&thing, &Thing<T>::const_member_func0));
-    Verifier<T>::verify0(callback((volatile Thing<T>*)&thing, &Thing<T>::volatile_member_func0));
-    Verifier<T>::verify0(callback((const volatile Thing<T>*)&thing, &Thing<T>::const_volatile_member_func0));
-    Verifier<T>::verify0(callback(&thing, &bound_func0<T>));
-    Verifier<T>::verify0(callback((const Thing<T>*)&thing, &const_func0<T>));
-    Verifier<T>::verify0(callback((volatile Thing<T>*)&thing, &volatile_func0<T>));
-    Verifier<T>::verify0(callback((const volatile Thing<T>*)&thing, &const_volatile_func0<T>));
 
-    Callback<T()> callback(static_func0);
-    Verifier<T>::verify0(callback);
-    callback.attach(&thing, &bound_func0<T>);
-    Verifier<T>::verify0(&callback, &Callback<T()>::call);
-    Verifier<T>::verify0((void*)&callback, &Callback<T()>::thunk);
+    Callback<T()> cb(static_func0);
+    Verifier<T>::verify0(cb);
+    cb = static_func0;
+    Verifier<T>::verify0(cb);
+    cb.attach(&thing, &bound_func0<T>);
+    Verifier<T>::verify0(&cb, &Callback<T()>::call);
+    Verifier<T>::verify0((void*)&cb, &Callback<T()>::thunk);
 }
 
 template <typename T>
@@ -232,20 +226,14 @@ void test_dispatch1() {
     Verifier<T>::verify1((volatile Thing<T>*)&thing, &volatile_func1<T>);
     Verifier<T>::verify1((const volatile Thing<T>*)&thing, &const_volatile_func1<T>);
     Verifier<T>::verify1(callback(static_func1<T>));
-    Verifier<T>::verify1(callback(&thing, &Thing<T>::member_func1));
-    Verifier<T>::verify1(callback((const Thing<T>*)&thing, &Thing<T>::const_member_func1));
-    Verifier<T>::verify1(callback((volatile Thing<T>*)&thing, &Thing<T>::volatile_member_func1));
-    Verifier<T>::verify1(callback((const volatile Thing<T>*)&thing, &Thing<T>::const_volatile_member_func1));
-    Verifier<T>::verify1(callback(&thing, &bound_func1<T>));
-    Verifier<T>::verify1(callback((const Thing<T>*)&thing, &const_func1<T>));
-    Verifier<T>::verify1(callback((volatile Thing<T>*)&thing, &volatile_func1<T>));
-    Verifier<T>::verify1(callback((const volatile Thing<T>*)&thing, &const_volatile_func1<T>));
 
-    Callback<T(T)> callback(static_func1);
-    Verifier<T>::verify1(callback);
-    callback.attach(&thing, &bound_func1<T>);
-    Verifier<T>::verify1(&callback, &Callback<T(T)>::call);
-    Verifier<T>::verify1((void*)&callback, &Callback<T(T)>::thunk);
+    Callback<T(T)> cb(static_func1);
+    Verifier<T>::verify1(cb);
+    cb = static_func1;
+    Verifier<T>::verify1(cb);
+    cb.attach(&thing, &bound_func1<T>);
+    Verifier<T>::verify1(&cb, &Callback<T(T)>::call);
+    Verifier<T>::verify1((void*)&cb, &Callback<T(T)>::thunk);
 }
 
 template <typename T>
@@ -261,20 +249,14 @@ void test_dispatch2() {
     Verifier<T>::verify2((volatile Thing<T>*)&thing, &volatile_func2<T>);
     Verifier<T>::verify2((const volatile Thing<T>*)&thing, &const_volatile_func2<T>);
     Verifier<T>::verify2(callback(static_func2<T>));
-    Verifier<T>::verify2(callback(&thing, &Thing<T>::member_func2));
-    Verifier<T>::verify2(callback((const Thing<T>*)&thing, &Thing<T>::const_member_func2));
-    Verifier<T>::verify2(callback((volatile Thing<T>*)&thing, &Thing<T>::volatile_member_func2));
-    Verifier<T>::verify2(callback((const volatile Thing<T>*)&thing, &Thing<T>::const_volatile_member_func2));
-    Verifier<T>::verify2(callback(&thing, &bound_func2<T>));
-    Verifier<T>::verify2(callback((const Thing<T>*)&thing, &const_func2<T>));
-    Verifier<T>::verify2(callback((volatile Thing<T>*)&thing, &volatile_func2<T>));
-    Verifier<T>::verify2(callback((const volatile Thing<T>*)&thing, &const_volatile_func2<T>));
 
-    Callback<T(T, T)> callback(static_func2);
-    Verifier<T>::verify2(callback);
-    callback.attach(&thing, &bound_func2<T>);
-    Verifier<T>::verify2(&callback, &Callback<T(T, T)>::call);
-    Verifier<T>::verify2((void*)&callback, &Callback<T(T, T)>::thunk);
+    Callback<T(T, T)> cb(static_func2);
+    Verifier<T>::verify2(cb);
+    cb = static_func2;
+    Verifier<T>::verify2(cb);
+    cb.attach(&thing, &bound_func2<T>);
+    Verifier<T>::verify2(&cb, &Callback<T(T, T)>::call);
+    Verifier<T>::verify2((void*)&cb, &Callback<T(T, T)>::thunk);
 }
 
 template <typename T>
@@ -290,20 +272,14 @@ void test_dispatch3() {
     Verifier<T>::verify3((volatile Thing<T>*)&thing, &volatile_func3<T>);
     Verifier<T>::verify3((const volatile Thing<T>*)&thing, &const_volatile_func3<T>);
     Verifier<T>::verify3(callback(static_func3<T>));
-    Verifier<T>::verify3(callback(&thing, &Thing<T>::member_func3));
-    Verifier<T>::verify3(callback((const Thing<T>*)&thing, &Thing<T>::const_member_func3));
-    Verifier<T>::verify3(callback((volatile Thing<T>*)&thing, &Thing<T>::volatile_member_func3));
-    Verifier<T>::verify3(callback((const volatile Thing<T>*)&thing, &Thing<T>::const_volatile_member_func3));
-    Verifier<T>::verify3(callback(&thing, &bound_func3<T>));
-    Verifier<T>::verify3(callback((const Thing<T>*)&thing, &const_func3<T>));
-    Verifier<T>::verify3(callback((volatile Thing<T>*)&thing, &volatile_func3<T>));
-    Verifier<T>::verify3(callback((const volatile Thing<T>*)&thing, &const_volatile_func3<T>));
 
-    Callback<T(T, T, T)> callback(static_func3);
-    Verifier<T>::verify3(callback);
-    callback.attach(&thing, &bound_func3<T>);
-    Verifier<T>::verify3(&callback, &Callback<T(T, T, T)>::call);
-    Verifier<T>::verify3((void*)&callback, &Callback<T(T, T, T)>::thunk);
+    Callback<T(T, T, T)> cb(static_func3);
+    Verifier<T>::verify3(cb);
+    cb = static_func3;
+    Verifier<T>::verify3(cb);
+    cb.attach(&thing, &bound_func3<T>);
+    Verifier<T>::verify3(&cb, &Callback<T(T, T, T)>::call);
+    Verifier<T>::verify3((void*)&cb, &Callback<T(T, T, T)>::thunk);
 }
 
 template <typename T>
@@ -319,20 +295,14 @@ void test_dispatch4() {
     Verifier<T>::verify4((volatile Thing<T>*)&thing, &volatile_func4<T>);
     Verifier<T>::verify4((const volatile Thing<T>*)&thing, &const_volatile_func4<T>);
     Verifier<T>::verify4(callback(static_func4<T>));
-    Verifier<T>::verify4(callback(&thing, &Thing<T>::member_func4));
-    Verifier<T>::verify4(callback((const Thing<T>*)&thing, &Thing<T>::const_member_func4));
-    Verifier<T>::verify4(callback((volatile Thing<T>*)&thing, &Thing<T>::volatile_member_func4));
-    Verifier<T>::verify4(callback((const volatile Thing<T>*)&thing, &Thing<T>::const_volatile_member_func4));
-    Verifier<T>::verify4(callback(&thing, &bound_func4<T>));
-    Verifier<T>::verify4(callback((const Thing<T>*)&thing, &const_func4<T>));
-    Verifier<T>::verify4(callback((volatile Thing<T>*)&thing, &volatile_func4<T>));
-    Verifier<T>::verify4(callback((const volatile Thing<T>*)&thing, &const_volatile_func4<T>));
 
-    Callback<T(T, T, T, T)> callback(static_func4);
-    Verifier<T>::verify4(callback);
-    callback.attach(&thing, &bound_func4<T>);
-    Verifier<T>::verify4(&callback, &Callback<T(T, T, T, T)>::call);
-    Verifier<T>::verify4((void*)&callback, &Callback<T(T, T, T, T)>::thunk);
+    Callback<T(T, T, T, T)> cb(static_func4);
+    Verifier<T>::verify4(cb);
+    cb = static_func4;
+    Verifier<T>::verify4(cb);
+    cb.attach(&thing, &bound_func4<T>);
+    Verifier<T>::verify4(&cb, &Callback<T(T, T, T, T)>::call);
+    Verifier<T>::verify4((void*)&cb, &Callback<T(T, T, T, T)>::thunk);
 }
 
 template <typename T>
@@ -348,20 +318,14 @@ void test_dispatch5() {
     Verifier<T>::verify5((volatile Thing<T>*)&thing, &volatile_func5<T>);
     Verifier<T>::verify5((const volatile Thing<T>*)&thing, &const_volatile_func5<T>);
     Verifier<T>::verify5(callback(static_func5<T>));
-    Verifier<T>::verify5(callback(&thing, &Thing<T>::member_func5));
-    Verifier<T>::verify5(callback((const Thing<T>*)&thing, &Thing<T>::const_member_func5));
-    Verifier<T>::verify5(callback((volatile Thing<T>*)&thing, &Thing<T>::volatile_member_func5));
-    Verifier<T>::verify5(callback((const volatile Thing<T>*)&thing, &Thing<T>::const_volatile_member_func5));
-    Verifier<T>::verify5(callback(&thing, &bound_func5<T>));
-    Verifier<T>::verify5(callback((const Thing<T>*)&thing, &const_func5<T>));
-    Verifier<T>::verify5(callback((volatile Thing<T>*)&thing, &volatile_func5<T>));
-    Verifier<T>::verify5(callback((const volatile Thing<T>*)&thing, &const_volatile_func5<T>));
 
-    Callback<T(T, T, T, T, T)> callback(static_func5);
-    Verifier<T>::verify5(callback);
-    callback.attach(&thing, &bound_func5<T>);
-    Verifier<T>::verify5(&callback, &Callback<T(T, T, T, T, T)>::call);
-    Verifier<T>::verify5((void*)&callback, &Callback<T(T, T, T, T, T)>::thunk);
+    Callback<T(T, T, T, T, T)> cb(static_func5);
+    Verifier<T>::verify5(cb);
+    cb = static_func5;
+    Verifier<T>::verify5(cb);
+    cb.attach(&thing, &bound_func5<T>);
+    Verifier<T>::verify5(&cb, &Callback<T(T, T, T, T, T)>::call);
+    Verifier<T>::verify5((void*)&cb, &Callback<T(T, T, T, T, T)>::thunk);
 }
 
 template <typename T>
diff --git a/hal/api/Callback.h b/hal/api/Callback.h
index 8a415bb6c4..fa78438655 100644
--- a/hal/api/Callback.h
+++ b/hal/api/Callback.h
@@ -18,6 +18,7 @@
 
 #include <string.h>
 #include <stdint.h>
+#include "mbed_assert.h"
 
 namespace mbed {
 
@@ -29,7 +30,9 @@ namespace mbed {
 template <typename F>
 class Callback;
 
-/** Templated function class
+/** Callback class based on template specialization
+ *
+ * @Note Synchronization level: Not protected
  */
 template <typename R>
 class Callback<R()> {
@@ -41,13 +44,6 @@ public:
         attach(func);
     }
 
-    /** Create a Callback with another Callback
-     *  @param func Callback to attach
-     */
-    Callback(const Callback<R()> &func) {
-        attach(func);
-    }
-
     /** Create a Callback with a static function and bound pointer
      *  @param obj  Pointer to object to bind to function
      *  @param func Static function to attach
@@ -57,16 +53,28 @@ public:
         attach(obj, func);
     }
 
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template<typename T>
     Callback(const T *obj, R (*func)(const T*)) {
         attach(obj, func);
     }
 
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template<typename T>
     Callback(volatile T *obj, R (*func)(volatile T*)) {
         attach(obj, func);
     }
 
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template<typename T>
     Callback(const volatile T *obj, R (*func)(const volatile T*)) {
         attach(obj, func);
@@ -81,16 +89,28 @@ public:
         attach(obj, func);
     }
 
+    /** Create a Callback with a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     Callback(const T *obj, R (T::*func)() const) {
         attach(obj, func);
     }
 
+    /** Create a Callback with a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     Callback(volatile T *obj, R (T::*func)() volatile) {
         attach(obj, func);
     }
 
+    /** Create a Callback with a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     Callback(const volatile T *obj, R (T::*func)() const volatile) {
         attach(obj, func);
@@ -101,13 +121,15 @@ public:
      */
     void attach(R (*func)()) {
         struct local {
-            static R _thunk(void*, void *func) {
-                return (*(R (**)())func)(
+            static R _thunk(void*, const void *func) {
+                return (*static_cast<R (*const *)()>(func))(
                         );
             }
         };
 
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = 0;
         _thunk = func ? &local::_thunk : 0;
     }
 
@@ -115,8 +137,9 @@ public:
      *  @param func The Callback to attach
      */
     void attach(const Callback<R()> &func) {
+        memset(&_func, 0, sizeof _func);
+        memcpy(&_func, &func._func, sizeof func);
         _obj = func._obj;
-        memcpy(&_func, &func._func, sizeof _func);
         _thunk = func._thunk;
     }
 
@@ -127,56 +150,72 @@ public:
     template <typename T>
     void attach(T *obj, R (*func)(T*)) {
         struct local {
-            static R _thunk(void *obj, void *func) {
-                return (*(R (**)(T*))func)(
+            static R _thunk(void *obj, const void *func) {
+                return (*static_cast<R (*const *)(T*)>(func))(
                         (T*)obj);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template <typename T>
     void attach(const T *obj, R (*func)(const T*)) {
         struct local {
-            static R _thunk(void *obj, void *func) {
-                return (*(R (**)(const T*))func)(
+            static R _thunk(void *obj, const void *func) {
+                return (*static_cast<R (*const *)(const T*)>(func))(
                         (const T*)obj);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template <typename T>
     void attach(volatile T *obj, R (*func)(volatile T*)) {
         struct local {
-            static R _thunk(void *obj, void *func) {
-                return (*(R (**)(volatile T*))func)(
+            static R _thunk(void *obj, const void *func) {
+                return (*static_cast<R (*const *)(volatile T*)>(func))(
                         (volatile T*)obj);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template <typename T>
     void attach(const volatile T *obj, R (*func)(const volatile T*)) {
         struct local {
-            static R _thunk(void *obj, void *func) {
-                return (*(R (**)(const volatile T*))func)(
+            static R _thunk(void *obj, const void *func) {
+                return (*static_cast<R (*const *)(const volatile T*)>(func))(
                         (const volatile T*)obj);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
@@ -187,71 +226,89 @@ public:
     template<typename T>
     void attach(T *obj, R (T::*func)()) {
         struct local {
-            static R _thunk(void *obj, void *func) {
-                return (((T*)obj)->*(*(R (T::**)())func))(
+            static R _thunk(void *obj, const void *func) {
+                return (((T*)obj)->*
+                        (*static_cast<R (T::*const *)()>(func)))(
                         );
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     void attach(const T *obj, R (T::*func)() const) {
         struct local {
-            static R _thunk(void *obj, void *func) {
-                return (((const T*)obj)->*(*(R (T::**)() const)func))(
+            static R _thunk(void *obj, const void *func) {
+                return (((const T*)obj)->*
+                        (*static_cast<R (T::*const *)() const>(func)))(
                         );
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     void attach(volatile T *obj, R (T::*func)() volatile) {
         struct local {
-            static R _thunk(void *obj, void *func) {
-                return (((volatile T*)obj)->*(*(R (T::**)() volatile)func))(
+            static R _thunk(void *obj, const void *func) {
+                return (((volatile T*)obj)->*
+                        (*static_cast<R (T::*const *)() volatile>(func)))(
                         );
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     void attach(const volatile T *obj, R (T::*func)() const volatile) {
         struct local {
-            static R _thunk(void *obj, void *func) {
-                return (((const volatile T*)obj)->*(*(R (T::**)() const volatile)func))(
+            static R _thunk(void *obj, const void *func) {
+                return (((const volatile T*)obj)->*
+                        (*static_cast<R (T::*const *)() const volatile>(func)))(
                         );
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
     /** Call the attached function
      */
-    R call() {
-        if (!_thunk) {
-            return (R)0;
-        }
+    R call() const {
+        MBED_ASSERT(_thunk);
         return _thunk(_obj, &_func);
     }
 
     /** Call the attached function
      */
-    R operator()() {
+    R operator()() const {
         return call();
     }
 
@@ -261,6 +318,18 @@ public:
         return _thunk;
     }
 
+    /** Test for equality
+     */
+    friend bool operator==(const Callback &l, const Callback &r) {
+        return memcmp(&l, &r, sizeof(Callback)) == 0;
+    }
+
+    /** Test for inequality
+     */
+    friend bool operator!=(const Callback &l, const Callback &r) {
+        return !(l == r);
+    }
+
     /** Static thunk for passing as C-style function
      *  @param func Callback to call passed as void pointer
      */
@@ -283,10 +352,12 @@ private:
     void *_obj;
 
     // Thunk registered on attach to dispatch calls
-    R (*_thunk)(void*, void*);
+    R (*_thunk)(void*, const void*);
 };
 
-/** Templated function class
+/** Callback class based on template specialization
+ *
+ * @Note Synchronization level: Not protected
  */
 template <typename R, typename A0>
 class Callback<R(A0)> {
@@ -298,13 +369,6 @@ public:
         attach(func);
     }
 
-    /** Create a Callback with another Callback
-     *  @param func Callback to attach
-     */
-    Callback(const Callback<R(A0)> &func) {
-        attach(func);
-    }
-
     /** Create a Callback with a static function and bound pointer
      *  @param obj  Pointer to object to bind to function
      *  @param func Static function to attach
@@ -314,16 +378,28 @@ public:
         attach(obj, func);
     }
 
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template<typename T>
     Callback(const T *obj, R (*func)(const T*, A0)) {
         attach(obj, func);
     }
 
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template<typename T>
     Callback(volatile T *obj, R (*func)(volatile T*, A0)) {
         attach(obj, func);
     }
 
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template<typename T>
     Callback(const volatile T *obj, R (*func)(const volatile T*, A0)) {
         attach(obj, func);
@@ -338,16 +414,28 @@ public:
         attach(obj, func);
     }
 
+    /** Create a Callback with a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     Callback(const T *obj, R (T::*func)(A0) const) {
         attach(obj, func);
     }
 
+    /** Create a Callback with a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     Callback(volatile T *obj, R (T::*func)(A0) volatile) {
         attach(obj, func);
     }
 
+    /** Create a Callback with a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     Callback(const volatile T *obj, R (T::*func)(A0) const volatile) {
         attach(obj, func);
@@ -358,13 +446,15 @@ public:
      */
     void attach(R (*func)(A0)) {
         struct local {
-            static R _thunk(void*, void *func, A0 a0) {
-                return (*(R (**)(A0))func)(
+            static R _thunk(void*, const void *func, A0 a0) {
+                return (*static_cast<R (*const *)(A0)>(func))(
                         a0);
             }
         };
 
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = 0;
         _thunk = func ? &local::_thunk : 0;
     }
 
@@ -372,8 +462,9 @@ public:
      *  @param func The Callback to attach
      */
     void attach(const Callback<R(A0)> &func) {
+        memset(&_func, 0, sizeof _func);
+        memcpy(&_func, &func._func, sizeof func);
         _obj = func._obj;
-        memcpy(&_func, &func._func, sizeof _func);
         _thunk = func._thunk;
     }
 
@@ -384,56 +475,72 @@ public:
     template <typename T>
     void attach(T *obj, R (*func)(T*, A0)) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0) {
-                return (*(R (**)(T*, A0))func)(
+            static R _thunk(void *obj, const void *func, A0 a0) {
+                return (*static_cast<R (*const *)(T*, A0)>(func))(
                         (T*)obj, a0);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template <typename T>
     void attach(const T *obj, R (*func)(const T*, A0)) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0) {
-                return (*(R (**)(const T*, A0))func)(
+            static R _thunk(void *obj, const void *func, A0 a0) {
+                return (*static_cast<R (*const *)(const T*, A0)>(func))(
                         (const T*)obj, a0);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template <typename T>
     void attach(volatile T *obj, R (*func)(volatile T*, A0)) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0) {
-                return (*(R (**)(volatile T*, A0))func)(
+            static R _thunk(void *obj, const void *func, A0 a0) {
+                return (*static_cast<R (*const *)(volatile T*, A0)>(func))(
                         (volatile T*)obj, a0);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template <typename T>
     void attach(const volatile T *obj, R (*func)(const volatile T*, A0)) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0) {
-                return (*(R (**)(const volatile T*, A0))func)(
+            static R _thunk(void *obj, const void *func, A0 a0) {
+                return (*static_cast<R (*const *)(const volatile T*, A0)>(func))(
                         (const volatile T*)obj, a0);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
@@ -444,71 +551,89 @@ public:
     template<typename T>
     void attach(T *obj, R (T::*func)(A0)) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0) {
-                return (((T*)obj)->*(*(R (T::**)(A0))func))(
+            static R _thunk(void *obj, const void *func, A0 a0) {
+                return (((T*)obj)->*
+                        (*static_cast<R (T::*const *)(A0)>(func)))(
                         a0);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     void attach(const T *obj, R (T::*func)(A0) const) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0) {
-                return (((const T*)obj)->*(*(R (T::**)(A0) const)func))(
+            static R _thunk(void *obj, const void *func, A0 a0) {
+                return (((const T*)obj)->*
+                        (*static_cast<R (T::*const *)(A0) const>(func)))(
                         a0);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     void attach(volatile T *obj, R (T::*func)(A0) volatile) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0) {
-                return (((volatile T*)obj)->*(*(R (T::**)(A0) volatile)func))(
+            static R _thunk(void *obj, const void *func, A0 a0) {
+                return (((volatile T*)obj)->*
+                        (*static_cast<R (T::*const *)(A0) volatile>(func)))(
                         a0);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     void attach(const volatile T *obj, R (T::*func)(A0) const volatile) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0) {
-                return (((const volatile T*)obj)->*(*(R (T::**)(A0) const volatile)func))(
+            static R _thunk(void *obj, const void *func, A0 a0) {
+                return (((const volatile T*)obj)->*
+                        (*static_cast<R (T::*const *)(A0) const volatile>(func)))(
                         a0);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
     /** Call the attached function
      */
-    R call(A0 a0) {
-        if (!_thunk) {
-            return (R)0;
-        }
+    R call(A0 a0) const {
+        MBED_ASSERT(_thunk);
         return _thunk(_obj, &_func, a0);
     }
 
     /** Call the attached function
      */
-    R operator()(A0 a0) {
+    R operator()(A0 a0) const {
         return call(a0);
     }
 
@@ -518,6 +643,18 @@ public:
         return _thunk;
     }
 
+    /** Test for equality
+     */
+    friend bool operator==(const Callback &l, const Callback &r) {
+        return memcmp(&l, &r, sizeof(Callback)) == 0;
+    }
+
+    /** Test for inequality
+     */
+    friend bool operator!=(const Callback &l, const Callback &r) {
+        return !(l == r);
+    }
+
     /** Static thunk for passing as C-style function
      *  @param func Callback to call passed as void pointer
      */
@@ -540,10 +677,12 @@ private:
     void *_obj;
 
     // Thunk registered on attach to dispatch calls
-    R (*_thunk)(void*, void*, A0);
+    R (*_thunk)(void*, const void*, A0);
 };
 
-/** Templated function class
+/** Callback class based on template specialization
+ *
+ * @Note Synchronization level: Not protected
  */
 template <typename R, typename A0, typename A1>
 class Callback<R(A0, A1)> {
@@ -555,13 +694,6 @@ public:
         attach(func);
     }
 
-    /** Create a Callback with another Callback
-     *  @param func Callback to attach
-     */
-    Callback(const Callback<R(A0, A1)> &func) {
-        attach(func);
-    }
-
     /** Create a Callback with a static function and bound pointer
      *  @param obj  Pointer to object to bind to function
      *  @param func Static function to attach
@@ -571,16 +703,28 @@ public:
         attach(obj, func);
     }
 
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template<typename T>
     Callback(const T *obj, R (*func)(const T*, A0, A1)) {
         attach(obj, func);
     }
 
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template<typename T>
     Callback(volatile T *obj, R (*func)(volatile T*, A0, A1)) {
         attach(obj, func);
     }
 
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template<typename T>
     Callback(const volatile T *obj, R (*func)(const volatile T*, A0, A1)) {
         attach(obj, func);
@@ -595,16 +739,28 @@ public:
         attach(obj, func);
     }
 
+    /** Create a Callback with a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     Callback(const T *obj, R (T::*func)(A0, A1) const) {
         attach(obj, func);
     }
 
+    /** Create a Callback with a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     Callback(volatile T *obj, R (T::*func)(A0, A1) volatile) {
         attach(obj, func);
     }
 
+    /** Create a Callback with a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     Callback(const volatile T *obj, R (T::*func)(A0, A1) const volatile) {
         attach(obj, func);
@@ -615,13 +771,15 @@ public:
      */
     void attach(R (*func)(A0, A1)) {
         struct local {
-            static R _thunk(void*, void *func, A0 a0, A1 a1) {
-                return (*(R (**)(A0, A1))func)(
+            static R _thunk(void*, const void *func, A0 a0, A1 a1) {
+                return (*static_cast<R (*const *)(A0, A1)>(func))(
                         a0, a1);
             }
         };
 
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = 0;
         _thunk = func ? &local::_thunk : 0;
     }
 
@@ -629,8 +787,9 @@ public:
      *  @param func The Callback to attach
      */
     void attach(const Callback<R(A0, A1)> &func) {
+        memset(&_func, 0, sizeof _func);
+        memcpy(&_func, &func._func, sizeof func);
         _obj = func._obj;
-        memcpy(&_func, &func._func, sizeof _func);
         _thunk = func._thunk;
     }
 
@@ -641,56 +800,72 @@ public:
     template <typename T>
     void attach(T *obj, R (*func)(T*, A0, A1)) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0, A1 a1) {
-                return (*(R (**)(T*, A0, A1))func)(
+            static R _thunk(void *obj, const void *func, A0 a0, A1 a1) {
+                return (*static_cast<R (*const *)(T*, A0, A1)>(func))(
                         (T*)obj, a0, a1);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template <typename T>
     void attach(const T *obj, R (*func)(const T*, A0, A1)) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0, A1 a1) {
-                return (*(R (**)(const T*, A0, A1))func)(
+            static R _thunk(void *obj, const void *func, A0 a0, A1 a1) {
+                return (*static_cast<R (*const *)(const T*, A0, A1)>(func))(
                         (const T*)obj, a0, a1);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template <typename T>
     void attach(volatile T *obj, R (*func)(volatile T*, A0, A1)) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0, A1 a1) {
-                return (*(R (**)(volatile T*, A0, A1))func)(
+            static R _thunk(void *obj, const void *func, A0 a0, A1 a1) {
+                return (*static_cast<R (*const *)(volatile T*, A0, A1)>(func))(
                         (volatile T*)obj, a0, a1);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template <typename T>
     void attach(const volatile T *obj, R (*func)(const volatile T*, A0, A1)) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0, A1 a1) {
-                return (*(R (**)(const volatile T*, A0, A1))func)(
+            static R _thunk(void *obj, const void *func, A0 a0, A1 a1) {
+                return (*static_cast<R (*const *)(const volatile T*, A0, A1)>(func))(
                         (const volatile T*)obj, a0, a1);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
@@ -701,71 +876,89 @@ public:
     template<typename T>
     void attach(T *obj, R (T::*func)(A0, A1)) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0, A1 a1) {
-                return (((T*)obj)->*(*(R (T::**)(A0, A1))func))(
+            static R _thunk(void *obj, const void *func, A0 a0, A1 a1) {
+                return (((T*)obj)->*
+                        (*static_cast<R (T::*const *)(A0, A1)>(func)))(
                         a0, a1);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     void attach(const T *obj, R (T::*func)(A0, A1) const) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0, A1 a1) {
-                return (((const T*)obj)->*(*(R (T::**)(A0, A1) const)func))(
+            static R _thunk(void *obj, const void *func, A0 a0, A1 a1) {
+                return (((const T*)obj)->*
+                        (*static_cast<R (T::*const *)(A0, A1) const>(func)))(
                         a0, a1);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     void attach(volatile T *obj, R (T::*func)(A0, A1) volatile) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0, A1 a1) {
-                return (((volatile T*)obj)->*(*(R (T::**)(A0, A1) volatile)func))(
+            static R _thunk(void *obj, const void *func, A0 a0, A1 a1) {
+                return (((volatile T*)obj)->*
+                        (*static_cast<R (T::*const *)(A0, A1) volatile>(func)))(
                         a0, a1);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     void attach(const volatile T *obj, R (T::*func)(A0, A1) const volatile) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0, A1 a1) {
-                return (((const volatile T*)obj)->*(*(R (T::**)(A0, A1) const volatile)func))(
+            static R _thunk(void *obj, const void *func, A0 a0, A1 a1) {
+                return (((const volatile T*)obj)->*
+                        (*static_cast<R (T::*const *)(A0, A1) const volatile>(func)))(
                         a0, a1);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
     /** Call the attached function
      */
-    R call(A0 a0, A1 a1) {
-        if (!_thunk) {
-            return (R)0;
-        }
+    R call(A0 a0, A1 a1) const {
+        MBED_ASSERT(_thunk);
         return _thunk(_obj, &_func, a0, a1);
     }
 
     /** Call the attached function
      */
-    R operator()(A0 a0, A1 a1) {
+    R operator()(A0 a0, A1 a1) const {
         return call(a0, a1);
     }
 
@@ -775,6 +968,18 @@ public:
         return _thunk;
     }
 
+    /** Test for equality
+     */
+    friend bool operator==(const Callback &l, const Callback &r) {
+        return memcmp(&l, &r, sizeof(Callback)) == 0;
+    }
+
+    /** Test for inequality
+     */
+    friend bool operator!=(const Callback &l, const Callback &r) {
+        return !(l == r);
+    }
+
     /** Static thunk for passing as C-style function
      *  @param func Callback to call passed as void pointer
      */
@@ -797,10 +1002,12 @@ private:
     void *_obj;
 
     // Thunk registered on attach to dispatch calls
-    R (*_thunk)(void*, void*, A0, A1);
+    R (*_thunk)(void*, const void*, A0, A1);
 };
 
-/** Templated function class
+/** Callback class based on template specialization
+ *
+ * @Note Synchronization level: Not protected
  */
 template <typename R, typename A0, typename A1, typename A2>
 class Callback<R(A0, A1, A2)> {
@@ -812,13 +1019,6 @@ public:
         attach(func);
     }
 
-    /** Create a Callback with another Callback
-     *  @param func Callback to attach
-     */
-    Callback(const Callback<R(A0, A1, A2)> &func) {
-        attach(func);
-    }
-
     /** Create a Callback with a static function and bound pointer
      *  @param obj  Pointer to object to bind to function
      *  @param func Static function to attach
@@ -828,16 +1028,28 @@ public:
         attach(obj, func);
     }
 
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template<typename T>
     Callback(const T *obj, R (*func)(const T*, A0, A1, A2)) {
         attach(obj, func);
     }
 
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template<typename T>
     Callback(volatile T *obj, R (*func)(volatile T*, A0, A1, A2)) {
         attach(obj, func);
     }
 
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template<typename T>
     Callback(const volatile T *obj, R (*func)(const volatile T*, A0, A1, A2)) {
         attach(obj, func);
@@ -852,16 +1064,28 @@ public:
         attach(obj, func);
     }
 
+    /** Create a Callback with a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     Callback(const T *obj, R (T::*func)(A0, A1, A2) const) {
         attach(obj, func);
     }
 
+    /** Create a Callback with a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     Callback(volatile T *obj, R (T::*func)(A0, A1, A2) volatile) {
         attach(obj, func);
     }
 
+    /** Create a Callback with a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     Callback(const volatile T *obj, R (T::*func)(A0, A1, A2) const volatile) {
         attach(obj, func);
@@ -872,13 +1096,15 @@ public:
      */
     void attach(R (*func)(A0, A1, A2)) {
         struct local {
-            static R _thunk(void*, void *func, A0 a0, A1 a1, A2 a2) {
-                return (*(R (**)(A0, A1, A2))func)(
+            static R _thunk(void*, const void *func, A0 a0, A1 a1, A2 a2) {
+                return (*static_cast<R (*const *)(A0, A1, A2)>(func))(
                         a0, a1, a2);
             }
         };
 
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = 0;
         _thunk = func ? &local::_thunk : 0;
     }
 
@@ -886,8 +1112,9 @@ public:
      *  @param func The Callback to attach
      */
     void attach(const Callback<R(A0, A1, A2)> &func) {
+        memset(&_func, 0, sizeof _func);
+        memcpy(&_func, &func._func, sizeof func);
         _obj = func._obj;
-        memcpy(&_func, &func._func, sizeof _func);
         _thunk = func._thunk;
     }
 
@@ -898,56 +1125,72 @@ public:
     template <typename T>
     void attach(T *obj, R (*func)(T*, A0, A1, A2)) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2) {
-                return (*(R (**)(T*, A0, A1, A2))func)(
+            static R _thunk(void *obj, const void *func, A0 a0, A1 a1, A2 a2) {
+                return (*static_cast<R (*const *)(T*, A0, A1, A2)>(func))(
                         (T*)obj, a0, a1, a2);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template <typename T>
     void attach(const T *obj, R (*func)(const T*, A0, A1, A2)) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2) {
-                return (*(R (**)(const T*, A0, A1, A2))func)(
+            static R _thunk(void *obj, const void *func, A0 a0, A1 a1, A2 a2) {
+                return (*static_cast<R (*const *)(const T*, A0, A1, A2)>(func))(
                         (const T*)obj, a0, a1, a2);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template <typename T>
     void attach(volatile T *obj, R (*func)(volatile T*, A0, A1, A2)) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2) {
-                return (*(R (**)(volatile T*, A0, A1, A2))func)(
+            static R _thunk(void *obj, const void *func, A0 a0, A1 a1, A2 a2) {
+                return (*static_cast<R (*const *)(volatile T*, A0, A1, A2)>(func))(
                         (volatile T*)obj, a0, a1, a2);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template <typename T>
     void attach(const volatile T *obj, R (*func)(const volatile T*, A0, A1, A2)) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2) {
-                return (*(R (**)(const volatile T*, A0, A1, A2))func)(
+            static R _thunk(void *obj, const void *func, A0 a0, A1 a1, A2 a2) {
+                return (*static_cast<R (*const *)(const volatile T*, A0, A1, A2)>(func))(
                         (const volatile T*)obj, a0, a1, a2);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
@@ -958,71 +1201,89 @@ public:
     template<typename T>
     void attach(T *obj, R (T::*func)(A0, A1, A2)) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2) {
-                return (((T*)obj)->*(*(R (T::**)(A0, A1, A2))func))(
+            static R _thunk(void *obj, const void *func, A0 a0, A1 a1, A2 a2) {
+                return (((T*)obj)->*
+                        (*static_cast<R (T::*const *)(A0, A1, A2)>(func)))(
                         a0, a1, a2);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     void attach(const T *obj, R (T::*func)(A0, A1, A2) const) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2) {
-                return (((const T*)obj)->*(*(R (T::**)(A0, A1, A2) const)func))(
+            static R _thunk(void *obj, const void *func, A0 a0, A1 a1, A2 a2) {
+                return (((const T*)obj)->*
+                        (*static_cast<R (T::*const *)(A0, A1, A2) const>(func)))(
                         a0, a1, a2);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     void attach(volatile T *obj, R (T::*func)(A0, A1, A2) volatile) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2) {
-                return (((volatile T*)obj)->*(*(R (T::**)(A0, A1, A2) volatile)func))(
+            static R _thunk(void *obj, const void *func, A0 a0, A1 a1, A2 a2) {
+                return (((volatile T*)obj)->*
+                        (*static_cast<R (T::*const *)(A0, A1, A2) volatile>(func)))(
                         a0, a1, a2);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     void attach(const volatile T *obj, R (T::*func)(A0, A1, A2) const volatile) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2) {
-                return (((const volatile T*)obj)->*(*(R (T::**)(A0, A1, A2) const volatile)func))(
+            static R _thunk(void *obj, const void *func, A0 a0, A1 a1, A2 a2) {
+                return (((const volatile T*)obj)->*
+                        (*static_cast<R (T::*const *)(A0, A1, A2) const volatile>(func)))(
                         a0, a1, a2);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
     /** Call the attached function
      */
-    R call(A0 a0, A1 a1, A2 a2) {
-        if (!_thunk) {
-            return (R)0;
-        }
+    R call(A0 a0, A1 a1, A2 a2) const {
+        MBED_ASSERT(_thunk);
         return _thunk(_obj, &_func, a0, a1, a2);
     }
 
     /** Call the attached function
      */
-    R operator()(A0 a0, A1 a1, A2 a2) {
+    R operator()(A0 a0, A1 a1, A2 a2) const {
         return call(a0, a1, a2);
     }
 
@@ -1032,6 +1293,18 @@ public:
         return _thunk;
     }
 
+    /** Test for equality
+     */
+    friend bool operator==(const Callback &l, const Callback &r) {
+        return memcmp(&l, &r, sizeof(Callback)) == 0;
+    }
+
+    /** Test for inequality
+     */
+    friend bool operator!=(const Callback &l, const Callback &r) {
+        return !(l == r);
+    }
+
     /** Static thunk for passing as C-style function
      *  @param func Callback to call passed as void pointer
      */
@@ -1054,10 +1327,12 @@ private:
     void *_obj;
 
     // Thunk registered on attach to dispatch calls
-    R (*_thunk)(void*, void*, A0, A1, A2);
+    R (*_thunk)(void*, const void*, A0, A1, A2);
 };
 
-/** Templated function class
+/** Callback class based on template specialization
+ *
+ * @Note Synchronization level: Not protected
  */
 template <typename R, typename A0, typename A1, typename A2, typename A3>
 class Callback<R(A0, A1, A2, A3)> {
@@ -1069,13 +1344,6 @@ public:
         attach(func);
     }
 
-    /** Create a Callback with another Callback
-     *  @param func Callback to attach
-     */
-    Callback(const Callback<R(A0, A1, A2, A3)> &func) {
-        attach(func);
-    }
-
     /** Create a Callback with a static function and bound pointer
      *  @param obj  Pointer to object to bind to function
      *  @param func Static function to attach
@@ -1085,16 +1353,28 @@ public:
         attach(obj, func);
     }
 
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template<typename T>
     Callback(const T *obj, R (*func)(const T*, A0, A1, A2, A3)) {
         attach(obj, func);
     }
 
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template<typename T>
     Callback(volatile T *obj, R (*func)(volatile T*, A0, A1, A2, A3)) {
         attach(obj, func);
     }
 
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template<typename T>
     Callback(const volatile T *obj, R (*func)(const volatile T*, A0, A1, A2, A3)) {
         attach(obj, func);
@@ -1109,16 +1389,28 @@ public:
         attach(obj, func);
     }
 
+    /** Create a Callback with a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     Callback(const T *obj, R (T::*func)(A0, A1, A2, A3) const) {
         attach(obj, func);
     }
 
+    /** Create a Callback with a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     Callback(volatile T *obj, R (T::*func)(A0, A1, A2, A3) volatile) {
         attach(obj, func);
     }
 
+    /** Create a Callback with a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     Callback(const volatile T *obj, R (T::*func)(A0, A1, A2, A3) const volatile) {
         attach(obj, func);
@@ -1129,13 +1421,15 @@ public:
      */
     void attach(R (*func)(A0, A1, A2, A3)) {
         struct local {
-            static R _thunk(void*, void *func, A0 a0, A1 a1, A2 a2, A3 a3) {
-                return (*(R (**)(A0, A1, A2, A3))func)(
+            static R _thunk(void*, const void *func, A0 a0, A1 a1, A2 a2, A3 a3) {
+                return (*static_cast<R (*const *)(A0, A1, A2, A3)>(func))(
                         a0, a1, a2, a3);
             }
         };
 
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = 0;
         _thunk = func ? &local::_thunk : 0;
     }
 
@@ -1143,8 +1437,9 @@ public:
      *  @param func The Callback to attach
      */
     void attach(const Callback<R(A0, A1, A2, A3)> &func) {
+        memset(&_func, 0, sizeof _func);
+        memcpy(&_func, &func._func, sizeof func);
         _obj = func._obj;
-        memcpy(&_func, &func._func, sizeof _func);
         _thunk = func._thunk;
     }
 
@@ -1155,56 +1450,72 @@ public:
     template <typename T>
     void attach(T *obj, R (*func)(T*, A0, A1, A2, A3)) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3) {
-                return (*(R (**)(T*, A0, A1, A2, A3))func)(
+            static R _thunk(void *obj, const void *func, A0 a0, A1 a1, A2 a2, A3 a3) {
+                return (*static_cast<R (*const *)(T*, A0, A1, A2, A3)>(func))(
                         (T*)obj, a0, a1, a2, a3);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template <typename T>
     void attach(const T *obj, R (*func)(const T*, A0, A1, A2, A3)) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3) {
-                return (*(R (**)(const T*, A0, A1, A2, A3))func)(
+            static R _thunk(void *obj, const void *func, A0 a0, A1 a1, A2 a2, A3 a3) {
+                return (*static_cast<R (*const *)(const T*, A0, A1, A2, A3)>(func))(
                         (const T*)obj, a0, a1, a2, a3);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template <typename T>
     void attach(volatile T *obj, R (*func)(volatile T*, A0, A1, A2, A3)) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3) {
-                return (*(R (**)(volatile T*, A0, A1, A2, A3))func)(
+            static R _thunk(void *obj, const void *func, A0 a0, A1 a1, A2 a2, A3 a3) {
+                return (*static_cast<R (*const *)(volatile T*, A0, A1, A2, A3)>(func))(
                         (volatile T*)obj, a0, a1, a2, a3);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template <typename T>
     void attach(const volatile T *obj, R (*func)(const volatile T*, A0, A1, A2, A3)) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3) {
-                return (*(R (**)(const volatile T*, A0, A1, A2, A3))func)(
+            static R _thunk(void *obj, const void *func, A0 a0, A1 a1, A2 a2, A3 a3) {
+                return (*static_cast<R (*const *)(const volatile T*, A0, A1, A2, A3)>(func))(
                         (const volatile T*)obj, a0, a1, a2, a3);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
@@ -1215,71 +1526,89 @@ public:
     template<typename T>
     void attach(T *obj, R (T::*func)(A0, A1, A2, A3)) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3) {
-                return (((T*)obj)->*(*(R (T::**)(A0, A1, A2, A3))func))(
+            static R _thunk(void *obj, const void *func, A0 a0, A1 a1, A2 a2, A3 a3) {
+                return (((T*)obj)->*
+                        (*static_cast<R (T::*const *)(A0, A1, A2, A3)>(func)))(
                         a0, a1, a2, a3);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     void attach(const T *obj, R (T::*func)(A0, A1, A2, A3) const) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3) {
-                return (((const T*)obj)->*(*(R (T::**)(A0, A1, A2, A3) const)func))(
+            static R _thunk(void *obj, const void *func, A0 a0, A1 a1, A2 a2, A3 a3) {
+                return (((const T*)obj)->*
+                        (*static_cast<R (T::*const *)(A0, A1, A2, A3) const>(func)))(
                         a0, a1, a2, a3);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     void attach(volatile T *obj, R (T::*func)(A0, A1, A2, A3) volatile) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3) {
-                return (((volatile T*)obj)->*(*(R (T::**)(A0, A1, A2, A3) volatile)func))(
+            static R _thunk(void *obj, const void *func, A0 a0, A1 a1, A2 a2, A3 a3) {
+                return (((volatile T*)obj)->*
+                        (*static_cast<R (T::*const *)(A0, A1, A2, A3) volatile>(func)))(
                         a0, a1, a2, a3);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     void attach(const volatile T *obj, R (T::*func)(A0, A1, A2, A3) const volatile) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3) {
-                return (((const volatile T*)obj)->*(*(R (T::**)(A0, A1, A2, A3) const volatile)func))(
+            static R _thunk(void *obj, const void *func, A0 a0, A1 a1, A2 a2, A3 a3) {
+                return (((const volatile T*)obj)->*
+                        (*static_cast<R (T::*const *)(A0, A1, A2, A3) const volatile>(func)))(
                         a0, a1, a2, a3);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
     /** Call the attached function
      */
-    R call(A0 a0, A1 a1, A2 a2, A3 a3) {
-        if (!_thunk) {
-            return (R)0;
-        }
+    R call(A0 a0, A1 a1, A2 a2, A3 a3) const {
+        MBED_ASSERT(_thunk);
         return _thunk(_obj, &_func, a0, a1, a2, a3);
     }
 
     /** Call the attached function
      */
-    R operator()(A0 a0, A1 a1, A2 a2, A3 a3) {
+    R operator()(A0 a0, A1 a1, A2 a2, A3 a3) const {
         return call(a0, a1, a2, a3);
     }
 
@@ -1289,6 +1618,18 @@ public:
         return _thunk;
     }
 
+    /** Test for equality
+     */
+    friend bool operator==(const Callback &l, const Callback &r) {
+        return memcmp(&l, &r, sizeof(Callback)) == 0;
+    }
+
+    /** Test for inequality
+     */
+    friend bool operator!=(const Callback &l, const Callback &r) {
+        return !(l == r);
+    }
+
     /** Static thunk for passing as C-style function
      *  @param func Callback to call passed as void pointer
      */
@@ -1311,10 +1652,12 @@ private:
     void *_obj;
 
     // Thunk registered on attach to dispatch calls
-    R (*_thunk)(void*, void*, A0, A1, A2, A3);
+    R (*_thunk)(void*, const void*, A0, A1, A2, A3);
 };
 
-/** Templated function class
+/** Callback class based on template specialization
+ *
+ * @Note Synchronization level: Not protected
  */
 template <typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
 class Callback<R(A0, A1, A2, A3, A4)> {
@@ -1326,13 +1669,6 @@ public:
         attach(func);
     }
 
-    /** Create a Callback with another Callback
-     *  @param func Callback to attach
-     */
-    Callback(const Callback<R(A0, A1, A2, A3, A4)> &func) {
-        attach(func);
-    }
-
     /** Create a Callback with a static function and bound pointer
      *  @param obj  Pointer to object to bind to function
      *  @param func Static function to attach
@@ -1342,16 +1678,28 @@ public:
         attach(obj, func);
     }
 
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template<typename T>
     Callback(const T *obj, R (*func)(const T*, A0, A1, A2, A3, A4)) {
         attach(obj, func);
     }
 
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template<typename T>
     Callback(volatile T *obj, R (*func)(volatile T*, A0, A1, A2, A3, A4)) {
         attach(obj, func);
     }
 
+    /** Create a Callback with a static function and bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template<typename T>
     Callback(const volatile T *obj, R (*func)(const volatile T*, A0, A1, A2, A3, A4)) {
         attach(obj, func);
@@ -1366,16 +1714,28 @@ public:
         attach(obj, func);
     }
 
+    /** Create a Callback with a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     Callback(const T *obj, R (T::*func)(A0, A1, A2, A3, A4) const) {
         attach(obj, func);
     }
 
+    /** Create a Callback with a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     Callback(volatile T *obj, R (T::*func)(A0, A1, A2, A3, A4) volatile) {
         attach(obj, func);
     }
 
+    /** Create a Callback with a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     Callback(const volatile T *obj, R (T::*func)(A0, A1, A2, A3, A4) const volatile) {
         attach(obj, func);
@@ -1386,13 +1746,15 @@ public:
      */
     void attach(R (*func)(A0, A1, A2, A3, A4)) {
         struct local {
-            static R _thunk(void*, void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
-                return (*(R (**)(A0, A1, A2, A3, A4))func)(
+            static R _thunk(void*, const void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
+                return (*static_cast<R (*const *)(A0, A1, A2, A3, A4)>(func))(
                         a0, a1, a2, a3, a4);
             }
         };
 
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = 0;
         _thunk = func ? &local::_thunk : 0;
     }
 
@@ -1400,8 +1762,9 @@ public:
      *  @param func The Callback to attach
      */
     void attach(const Callback<R(A0, A1, A2, A3, A4)> &func) {
+        memset(&_func, 0, sizeof _func);
+        memcpy(&_func, &func._func, sizeof func);
         _obj = func._obj;
-        memcpy(&_func, &func._func, sizeof _func);
         _thunk = func._thunk;
     }
 
@@ -1412,56 +1775,72 @@ public:
     template <typename T>
     void attach(T *obj, R (*func)(T*, A0, A1, A2, A3, A4)) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
-                return (*(R (**)(T*, A0, A1, A2, A3, A4))func)(
+            static R _thunk(void *obj, const void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
+                return (*static_cast<R (*const *)(T*, A0, A1, A2, A3, A4)>(func))(
                         (T*)obj, a0, a1, a2, a3, a4);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template <typename T>
     void attach(const T *obj, R (*func)(const T*, A0, A1, A2, A3, A4)) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
-                return (*(R (**)(const T*, A0, A1, A2, A3, A4))func)(
+            static R _thunk(void *obj, const void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
+                return (*static_cast<R (*const *)(const T*, A0, A1, A2, A3, A4)>(func))(
                         (const T*)obj, a0, a1, a2, a3, a4);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template <typename T>
     void attach(volatile T *obj, R (*func)(volatile T*, A0, A1, A2, A3, A4)) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
-                return (*(R (**)(volatile T*, A0, A1, A2, A3, A4))func)(
+            static R _thunk(void *obj, const void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
+                return (*static_cast<R (*const *)(volatile T*, A0, A1, A2, A3, A4)>(func))(
                         (volatile T*)obj, a0, a1, a2, a3, a4);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a static function with a bound pointer
+     *  @param obj  Pointer to object to bind to function
+     *  @param func Static function to attach
+     */
     template <typename T>
     void attach(const volatile T *obj, R (*func)(const volatile T*, A0, A1, A2, A3, A4)) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
-                return (*(R (**)(const volatile T*, A0, A1, A2, A3, A4))func)(
+            static R _thunk(void *obj, const void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
+                return (*static_cast<R (*const *)(const volatile T*, A0, A1, A2, A3, A4)>(func))(
                         (const volatile T*)obj, a0, a1, a2, a3, a4);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
@@ -1472,71 +1851,89 @@ public:
     template<typename T>
     void attach(T *obj, R (T::*func)(A0, A1, A2, A3, A4)) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
-                return (((T*)obj)->*(*(R (T::**)(A0, A1, A2, A3, A4))func))(
+            static R _thunk(void *obj, const void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
+                return (((T*)obj)->*
+                        (*static_cast<R (T::*const *)(A0, A1, A2, A3, A4)>(func)))(
                         a0, a1, a2, a3, a4);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     void attach(const T *obj, R (T::*func)(A0, A1, A2, A3, A4) const) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
-                return (((const T*)obj)->*(*(R (T::**)(A0, A1, A2, A3, A4) const)func))(
+            static R _thunk(void *obj, const void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
+                return (((const T*)obj)->*
+                        (*static_cast<R (T::*const *)(A0, A1, A2, A3, A4) const>(func)))(
                         a0, a1, a2, a3, a4);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     void attach(volatile T *obj, R (T::*func)(A0, A1, A2, A3, A4) volatile) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
-                return (((volatile T*)obj)->*(*(R (T::**)(A0, A1, A2, A3, A4) volatile)func))(
+            static R _thunk(void *obj, const void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
+                return (((volatile T*)obj)->*
+                        (*static_cast<R (T::*const *)(A0, A1, A2, A3, A4) volatile>(func)))(
                         a0, a1, a2, a3, a4);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
+    /** Attach a member function
+     *  @param obj  Pointer to object to invoke member function on
+     *  @param func Member function to attach
+     */
     template<typename T>
     void attach(const volatile T *obj, R (T::*func)(A0, A1, A2, A3, A4) const volatile) {
         struct local {
-            static R _thunk(void *obj, void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
-                return (((const volatile T*)obj)->*(*(R (T::**)(A0, A1, A2, A3, A4) const volatile)func))(
+            static R _thunk(void *obj, const void *func, A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
+                return (((const volatile T*)obj)->*
+                        (*static_cast<R (T::*const *)(A0, A1, A2, A3, A4) const volatile>(func)))(
                         a0, a1, a2, a3, a4);
             }
         };
 
-        _obj = (void*)obj;
+        memset(&_func, 0, sizeof _func);
         memcpy(&_func, &func, sizeof func);
+        _obj = (void*)obj;
         _thunk = &local::_thunk;
     }
 
     /** Call the attached function
      */
-    R call(A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
-        if (!_thunk) {
-            return (R)0;
-        }
+    R call(A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) const {
+        MBED_ASSERT(_thunk);
         return _thunk(_obj, &_func, a0, a1, a2, a3, a4);
     }
 
     /** Call the attached function
      */
-    R operator()(A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) {
+    R operator()(A0 a0, A1 a1, A2 a2, A3 a3, A4 a4) const {
         return call(a0, a1, a2, a3, a4);
     }
 
@@ -1546,6 +1943,18 @@ public:
         return _thunk;
     }
 
+    /** Test for equality
+     */
+    friend bool operator==(const Callback &l, const Callback &r) {
+        return memcmp(&l, &r, sizeof(Callback)) == 0;
+    }
+
+    /** Test for inequality
+     */
+    friend bool operator!=(const Callback &l, const Callback &r) {
+        return !(l == r);
+    }
+
     /** Static thunk for passing as C-style function
      *  @param func Callback to call passed as void pointer
      */
@@ -1568,307 +1977,661 @@ private:
     void *_obj;
 
     // Thunk registered on attach to dispatch calls
-    R (*_thunk)(void*, void*, A0, A1, A2, A3, A4);
+    R (*_thunk)(void*, const void*, A0, A1, A2, A3, A4);
 };
 
+// Internally used event type
 typedef Callback<void(int)> event_callback_t;
 
 
 /** Create a callback class with type infered from the arguments
  *
- *  @param obj  Optional pointer to object to bind to function
  *  @param func Static function to attach
- *  @return     Callback with type infered from arguments
+ *  @return     Callback with infered type
  */
 template <typename R>
 Callback<R()> callback(R (*func)() = 0) {
     return Callback<R()>(func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename R>
 Callback<R()> callback(const Callback<R()> &func) {
     return Callback<R()>(func);
 }
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename T, typename R>
 Callback<R()> callback(T *obj, R (*func)(T*)) {
     return Callback<R()>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename T, typename R>
 Callback<R()> callback(const T *obj, R (*func)(const T*)) {
     return Callback<R()>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename T, typename R>
 Callback<R()> callback(volatile T *obj, R (*func)(volatile T*)) {
     return Callback<R()>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename T, typename R>
 Callback<R()> callback(const volatile T *obj, R (*func)(const volatile T*)) {
     return Callback<R()>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template<typename T, typename R>
 Callback<R()> callback(T *obj, R (T::*func)()) {
     return Callback<R()>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template<typename T, typename R>
 Callback<R()> callback(const T *obj, R (T::*func)() const) {
     return Callback<R()>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template<typename T, typename R>
 Callback<R()> callback(volatile T *obj, R (T::*func)() volatile) {
     return Callback<R()>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template<typename T, typename R>
 Callback<R()> callback(const volatile T *obj, R (T::*func)() const volatile) {
     return Callback<R()>(obj, func);
 }
 
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename R, typename A0>
 Callback<R(A0)> callback(R (*func)(A0) = 0) {
     return Callback<R(A0)>(func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename R, typename A0>
 Callback<R(A0)> callback(const Callback<R(A0)> &func) {
     return Callback<R(A0)>(func);
 }
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename T, typename R, typename A0>
 Callback<R(A0)> callback(T *obj, R (*func)(T*, A0)) {
     return Callback<R(A0)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename T, typename R, typename A0>
 Callback<R(A0)> callback(const T *obj, R (*func)(const T*, A0)) {
     return Callback<R(A0)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename T, typename R, typename A0>
 Callback<R(A0)> callback(volatile T *obj, R (*func)(volatile T*, A0)) {
     return Callback<R(A0)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename T, typename R, typename A0>
 Callback<R(A0)> callback(const volatile T *obj, R (*func)(const volatile T*, A0)) {
     return Callback<R(A0)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template<typename T, typename R, typename A0>
 Callback<R(A0)> callback(T *obj, R (T::*func)(A0)) {
     return Callback<R(A0)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template<typename T, typename R, typename A0>
 Callback<R(A0)> callback(const T *obj, R (T::*func)(A0) const) {
     return Callback<R(A0)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template<typename T, typename R, typename A0>
 Callback<R(A0)> callback(volatile T *obj, R (T::*func)(A0) volatile) {
     return Callback<R(A0)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template<typename T, typename R, typename A0>
 Callback<R(A0)> callback(const volatile T *obj, R (T::*func)(A0) const volatile) {
     return Callback<R(A0)>(obj, func);
 }
 
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename R, typename A0, typename A1>
 Callback<R(A0, A1)> callback(R (*func)(A0, A1) = 0) {
     return Callback<R(A0, A1)>(func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename R, typename A0, typename A1>
 Callback<R(A0, A1)> callback(const Callback<R(A0, A1)> &func) {
     return Callback<R(A0, A1)>(func);
 }
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename T, typename R, typename A0, typename A1>
 Callback<R(A0, A1)> callback(T *obj, R (*func)(T*, A0, A1)) {
     return Callback<R(A0, A1)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename T, typename R, typename A0, typename A1>
 Callback<R(A0, A1)> callback(const T *obj, R (*func)(const T*, A0, A1)) {
     return Callback<R(A0, A1)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename T, typename R, typename A0, typename A1>
 Callback<R(A0, A1)> callback(volatile T *obj, R (*func)(volatile T*, A0, A1)) {
     return Callback<R(A0, A1)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename T, typename R, typename A0, typename A1>
 Callback<R(A0, A1)> callback(const volatile T *obj, R (*func)(const volatile T*, A0, A1)) {
     return Callback<R(A0, A1)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template<typename T, typename R, typename A0, typename A1>
 Callback<R(A0, A1)> callback(T *obj, R (T::*func)(A0, A1)) {
     return Callback<R(A0, A1)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template<typename T, typename R, typename A0, typename A1>
 Callback<R(A0, A1)> callback(const T *obj, R (T::*func)(A0, A1) const) {
     return Callback<R(A0, A1)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template<typename T, typename R, typename A0, typename A1>
 Callback<R(A0, A1)> callback(volatile T *obj, R (T::*func)(A0, A1) volatile) {
     return Callback<R(A0, A1)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template<typename T, typename R, typename A0, typename A1>
 Callback<R(A0, A1)> callback(const volatile T *obj, R (T::*func)(A0, A1) const volatile) {
     return Callback<R(A0, A1)>(obj, func);
 }
 
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename R, typename A0, typename A1, typename A2>
 Callback<R(A0, A1, A2)> callback(R (*func)(A0, A1, A2) = 0) {
     return Callback<R(A0, A1, A2)>(func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename R, typename A0, typename A1, typename A2>
 Callback<R(A0, A1, A2)> callback(const Callback<R(A0, A1, A2)> &func) {
     return Callback<R(A0, A1, A2)>(func);
 }
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename T, typename R, typename A0, typename A1, typename A2>
 Callback<R(A0, A1, A2)> callback(T *obj, R (*func)(T*, A0, A1, A2)) {
     return Callback<R(A0, A1, A2)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename T, typename R, typename A0, typename A1, typename A2>
 Callback<R(A0, A1, A2)> callback(const T *obj, R (*func)(const T*, A0, A1, A2)) {
     return Callback<R(A0, A1, A2)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename T, typename R, typename A0, typename A1, typename A2>
 Callback<R(A0, A1, A2)> callback(volatile T *obj, R (*func)(volatile T*, A0, A1, A2)) {
     return Callback<R(A0, A1, A2)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename T, typename R, typename A0, typename A1, typename A2>
 Callback<R(A0, A1, A2)> callback(const volatile T *obj, R (*func)(const volatile T*, A0, A1, A2)) {
     return Callback<R(A0, A1, A2)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template<typename T, typename R, typename A0, typename A1, typename A2>
 Callback<R(A0, A1, A2)> callback(T *obj, R (T::*func)(A0, A1, A2)) {
     return Callback<R(A0, A1, A2)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template<typename T, typename R, typename A0, typename A1, typename A2>
 Callback<R(A0, A1, A2)> callback(const T *obj, R (T::*func)(A0, A1, A2) const) {
     return Callback<R(A0, A1, A2)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template<typename T, typename R, typename A0, typename A1, typename A2>
 Callback<R(A0, A1, A2)> callback(volatile T *obj, R (T::*func)(A0, A1, A2) volatile) {
     return Callback<R(A0, A1, A2)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template<typename T, typename R, typename A0, typename A1, typename A2>
 Callback<R(A0, A1, A2)> callback(const volatile T *obj, R (T::*func)(A0, A1, A2) const volatile) {
     return Callback<R(A0, A1, A2)>(obj, func);
 }
 
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename R, typename A0, typename A1, typename A2, typename A3>
 Callback<R(A0, A1, A2, A3)> callback(R (*func)(A0, A1, A2, A3) = 0) {
     return Callback<R(A0, A1, A2, A3)>(func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename R, typename A0, typename A1, typename A2, typename A3>
 Callback<R(A0, A1, A2, A3)> callback(const Callback<R(A0, A1, A2, A3)> &func) {
     return Callback<R(A0, A1, A2, A3)>(func);
 }
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename T, typename R, typename A0, typename A1, typename A2, typename A3>
 Callback<R(A0, A1, A2, A3)> callback(T *obj, R (*func)(T*, A0, A1, A2, A3)) {
     return Callback<R(A0, A1, A2, A3)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename T, typename R, typename A0, typename A1, typename A2, typename A3>
 Callback<R(A0, A1, A2, A3)> callback(const T *obj, R (*func)(const T*, A0, A1, A2, A3)) {
     return Callback<R(A0, A1, A2, A3)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename T, typename R, typename A0, typename A1, typename A2, typename A3>
 Callback<R(A0, A1, A2, A3)> callback(volatile T *obj, R (*func)(volatile T*, A0, A1, A2, A3)) {
     return Callback<R(A0, A1, A2, A3)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename T, typename R, typename A0, typename A1, typename A2, typename A3>
 Callback<R(A0, A1, A2, A3)> callback(const volatile T *obj, R (*func)(const volatile T*, A0, A1, A2, A3)) {
     return Callback<R(A0, A1, A2, A3)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template<typename T, typename R, typename A0, typename A1, typename A2, typename A3>
 Callback<R(A0, A1, A2, A3)> callback(T *obj, R (T::*func)(A0, A1, A2, A3)) {
     return Callback<R(A0, A1, A2, A3)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template<typename T, typename R, typename A0, typename A1, typename A2, typename A3>
 Callback<R(A0, A1, A2, A3)> callback(const T *obj, R (T::*func)(A0, A1, A2, A3) const) {
     return Callback<R(A0, A1, A2, A3)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template<typename T, typename R, typename A0, typename A1, typename A2, typename A3>
 Callback<R(A0, A1, A2, A3)> callback(volatile T *obj, R (T::*func)(A0, A1, A2, A3) volatile) {
     return Callback<R(A0, A1, A2, A3)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template<typename T, typename R, typename A0, typename A1, typename A2, typename A3>
 Callback<R(A0, A1, A2, A3)> callback(const volatile T *obj, R (T::*func)(A0, A1, A2, A3) const volatile) {
     return Callback<R(A0, A1, A2, A3)>(obj, func);
 }
 
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
 Callback<R(A0, A1, A2, A3, A4)> callback(R (*func)(A0, A1, A2, A3, A4) = 0) {
     return Callback<R(A0, A1, A2, A3, A4)>(func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
 Callback<R(A0, A1, A2, A3, A4)> callback(const Callback<R(A0, A1, A2, A3, A4)> &func) {
     return Callback<R(A0, A1, A2, A3, A4)>(func);
 }
+
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename T, typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
 Callback<R(A0, A1, A2, A3, A4)> callback(T *obj, R (*func)(T*, A0, A1, A2, A3, A4)) {
     return Callback<R(A0, A1, A2, A3, A4)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename T, typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
 Callback<R(A0, A1, A2, A3, A4)> callback(const T *obj, R (*func)(const T*, A0, A1, A2, A3, A4)) {
     return Callback<R(A0, A1, A2, A3, A4)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename T, typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
 Callback<R(A0, A1, A2, A3, A4)> callback(volatile T *obj, R (*func)(volatile T*, A0, A1, A2, A3, A4)) {
     return Callback<R(A0, A1, A2, A3, A4)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template <typename T, typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
 Callback<R(A0, A1, A2, A3, A4)> callback(const volatile T *obj, R (*func)(const volatile T*, A0, A1, A2, A3, A4)) {
     return Callback<R(A0, A1, A2, A3, A4)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template<typename T, typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
 Callback<R(A0, A1, A2, A3, A4)> callback(T *obj, R (T::*func)(A0, A1, A2, A3, A4)) {
     return Callback<R(A0, A1, A2, A3, A4)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template<typename T, typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
 Callback<R(A0, A1, A2, A3, A4)> callback(const T *obj, R (T::*func)(A0, A1, A2, A3, A4) const) {
     return Callback<R(A0, A1, A2, A3, A4)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template<typename T, typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
 Callback<R(A0, A1, A2, A3, A4)> callback(volatile T *obj, R (T::*func)(A0, A1, A2, A3, A4) volatile) {
     return Callback<R(A0, A1, A2, A3, A4)>(obj, func);
 }
 
+/** Create a callback class with type infered from the arguments
+ *
+ *  @param obj  Optional pointer to object to bind to function
+ *  @param func Static function to attach
+ *  @return     Callback with infered type
+ */
 template<typename T, typename R, typename A0, typename A1, typename A2, typename A3, typename A4>
 Callback<R(A0, A1, A2, A3, A4)> callback(const volatile T *obj, R (T::*func)(A0, A1, A2, A3, A4) const volatile) {
     return Callback<R(A0, A1, A2, A3, A4)>(obj, func);
diff --git a/hal/api/FunctionPointer.h b/hal/api/FunctionPointer.h
index 1626e3e483..af51a8c929 100644
--- a/hal/api/FunctionPointer.h
+++ b/hal/api/FunctionPointer.h
@@ -43,6 +43,18 @@ public:
     R (*get_function())(A1) {
         return *reinterpret_cast<R (**)(A1)>(this);
     }
+
+    R call(A1 a1) const {
+        if (!Callback<R(A1)>::operator bool()) {
+            return (R)0;
+        }
+
+        return Callback<R(A1)>::call(a1);
+    }
+
+    R operator()(A1 a1) const {
+        return Callback<R(A1)>::call(a1);
+    }
 };
 
 template <typename R>
@@ -62,6 +74,18 @@ public:
     R (*get_function())() {
         return *reinterpret_cast<R (**)()>(this);
     }
+
+    R call() const {
+        if (!Callback<R()>::operator bool()) {
+            return (R)0;
+        }
+
+        return Callback<R()>::call();
+    }
+
+    R operator()() const {
+        return Callback<R()>::call();
+    }
 };
 
 typedef FunctionPointerArg1<void, void> FunctionPointer;
diff --git a/hal/common/CAN.cpp b/hal/common/CAN.cpp
index 780a106b73..84355b0230 100644
--- a/hal/common/CAN.cpp
+++ b/hal/common/CAN.cpp
@@ -21,8 +21,15 @@
 
 namespace mbed {
 
+static void donothing() {}
+
 CAN::CAN(PinName rd, PinName td) : _can(), _irq() {
     // No lock needed in constructor
+
+    for (int i = 0; i < sizeof _irq / sizeof _irq[0]; i++) {
+        _irq[i].attach(donothing);
+    }
+
     can_init(&_can, rd, td);
     can_irq_init(&_can, (&CAN::_irq_handler), (uint32_t)this);
 }
@@ -100,6 +107,7 @@ void CAN::attach(Callback<void()> func, IrqType type) {
         _irq[(CanIrqType)type].attach(func);
         can_irq_set(&_can, (CanIrqType)type, 1);
     } else {
+        _irq[(CanIrqType)type].attach(donothing);
         can_irq_set(&_can, (CanIrqType)type, 0);
     }
     unlock();
diff --git a/hal/common/InterruptIn.cpp b/hal/common/InterruptIn.cpp
index 0e5bde9bc2..d3986e8893 100644
--- a/hal/common/InterruptIn.cpp
+++ b/hal/common/InterruptIn.cpp
@@ -19,11 +19,17 @@
 
 namespace mbed {
 
+static void donothing() {}
+
 InterruptIn::InterruptIn(PinName pin) : gpio(),
                                         gpio_irq(),
                                         _rise(),
                                         _fall() {
     // No lock needed in the constructor
+
+    _rise.attach(donothing);
+    _fall.attach(donothing);
+
     gpio_irq_init(&gpio_irq, pin, (&InterruptIn::_irq_handler), (uint32_t)this);
     gpio_init_in(&gpio, pin);
 }
@@ -50,7 +56,7 @@ void InterruptIn::rise(Callback<void()> func) {
         _rise.attach(func);
         gpio_irq_set(&gpio_irq, IRQ_RISE, 1);
     } else {
-        _rise.attach(NULL);
+        _rise.attach(donothing);
         gpio_irq_set(&gpio_irq, IRQ_RISE, 0);
     }
     core_util_critical_section_exit();
@@ -62,7 +68,7 @@ void InterruptIn::fall(Callback<void()> func) {
         _fall.attach(func);
         gpio_irq_set(&gpio_irq, IRQ_FALL, 1);
     } else {
-        _fall.attach(NULL);
+        _fall.attach(donothing);
         gpio_irq_set(&gpio_irq, IRQ_FALL, 0);
     }
     core_util_critical_section_exit();
diff --git a/hal/common/SerialBase.cpp b/hal/common/SerialBase.cpp
index 891c450975..d75e479418 100644
--- a/hal/common/SerialBase.cpp
+++ b/hal/common/SerialBase.cpp
@@ -21,6 +21,8 @@
 
 namespace mbed {
 
+static void donothing() {};
+
 SerialBase::SerialBase(PinName tx, PinName rx) :
 #if DEVICE_SERIAL_ASYNCH
                                                  _thunk_irq(this), _tx_usage(DMA_USAGE_NEVER),
@@ -29,6 +31,10 @@ SerialBase::SerialBase(PinName tx, PinName rx) :
                                                 _serial(), _baud(9600) {
     // No lock needed in the constructor
 
+    for (int i = 0; i < sizeof _irq / sizeof _irq[0]; i++) {
+        _irq[i].attach(donothing);
+    }
+
     serial_init(&_serial, tx, rx);
     serial_irq_handler(&_serial, SerialBase::_irq_handler, (uint32_t)this);
 }
@@ -69,6 +75,7 @@ void SerialBase::attach(Callback<void()> func, IrqType type) {
         _irq[type].attach(func);
         serial_irq_set(&_serial, (SerialIrq)type, 1);
     } else {
+        _irq[type].attach(donothing);
         serial_irq_set(&_serial, (SerialIrq)type, 0);
     }
     core_util_critical_section_exit();

From 5c0f39f190dace90c1428c1b64d758db6561939c Mon Sep 17 00:00:00 2001
From: Christopher Haster <chaster@utexas.edu>
Date: Thu, 25 Aug 2016 10:36:29 -0500
Subject: [PATCH 3/3] Split callback test into multiple tests based on types

As the templated tests grew, the resulting binary exceeded a
flash size of 64K. This caused the test to incorrectly fail on
small devices.

Moved and split into the following:
TESTS/mbed_functional/callback
TESTS/mbed_functional/callback_small
TESTS/mbed_functional/callback_big
TESTS/mbed_functional/functionpointer
---
 TESTS/mbed_functional/callback/main.cpp       | 351 ++++++++++++++++++
 TESTS/mbed_functional/callback_big/main.cpp   | 351 ++++++++++++++++++
 .../callback_small}/main.cpp                  |  33 --
 .../mbed_functional/functionpointer/main.cpp  | 225 +++++++++++
 4 files changed, 927 insertions(+), 33 deletions(-)
 create mode 100644 TESTS/mbed_functional/callback/main.cpp
 create mode 100644 TESTS/mbed_functional/callback_big/main.cpp
 rename TESTS/{mbed_drivers/callback => mbed_functional/callback_small}/main.cpp (91%)
 create mode 100644 TESTS/mbed_functional/functionpointer/main.cpp

diff --git a/TESTS/mbed_functional/callback/main.cpp b/TESTS/mbed_functional/callback/main.cpp
new file mode 100644
index 0000000000..8442448e53
--- /dev/null
+++ b/TESTS/mbed_functional/callback/main.cpp
@@ -0,0 +1,351 @@
+#include "mbed.h"
+#include "greentea-client/test_env.h"
+#include "unity.h"
+#include "utest.h"
+
+using namespace utest::v1;
+
+
+// static functions
+template <typename T>
+T static_func0() { return 0; }
+template <typename T>
+T static_func1(T a0) { return 0 | a0; }
+template <typename T>
+T static_func2(T a0, T a1) { return 0 | a0 | a1; }
+template <typename T>
+T static_func3(T a0, T a1, T a2) { return 0 | a0 | a1 | a2; }
+template <typename T>
+T static_func4(T a0, T a1, T a2, T a3) { return 0 | a0 | a1 | a2 | a3; }
+template <typename T>
+T static_func5(T a0, T a1, T a2, T a3, T a4) { return 0 | a0 | a1 | a2 | a3 | a4; }
+
+// class functions
+template <typename T>
+struct Thing {
+    T t;
+    Thing() : t(0x80) {}
+
+    T member_func0() { return t; }
+    T member_func1(T a0) { return t | a0; }
+    T member_func2(T a0, T a1) { return t | a0 | a1; }
+    T member_func3(T a0, T a1, T a2) { return t | a0 | a1 | a2; }
+    T member_func4(T a0, T a1, T a2, T a3) { return t | a0 | a1 | a2 | a3; }
+    T member_func5(T a0, T a1, T a2, T a3, T a4) { return t | a0 | a1 | a2 | a3 | a4; }
+
+    T const_member_func0() const { return t; }
+    T const_member_func1(T a0) const { return t | a0; }
+    T const_member_func2(T a0, T a1) const { return t | a0 | a1; }
+    T const_member_func3(T a0, T a1, T a2) const { return t | a0 | a1 | a2; }
+    T const_member_func4(T a0, T a1, T a2, T a3) const { return t | a0 | a1 | a2 | a3; }
+    T const_member_func5(T a0, T a1, T a2, T a3, T a4) const { return t | a0 | a1 | a2 | a3 | a4; }
+
+    T volatile_member_func0() volatile { return t; }
+    T volatile_member_func1(T a0) volatile { return t | a0; }
+    T volatile_member_func2(T a0, T a1) volatile { return t | a0 | a1; }
+    T volatile_member_func3(T a0, T a1, T a2) volatile { return t | a0 | a1 | a2; }
+    T volatile_member_func4(T a0, T a1, T a2, T a3) volatile { return t | a0 | a1 | a2 | a3; }
+    T volatile_member_func5(T a0, T a1, T a2, T a3, T a4) volatile { return t | a0 | a1 | a2 | a3 | a4; }
+
+    T const_volatile_member_func0() const volatile { return t; }
+    T const_volatile_member_func1(T a0) const volatile { return t | a0; }
+    T const_volatile_member_func2(T a0, T a1) const volatile { return t | a0 | a1; }
+    T const_volatile_member_func3(T a0, T a1, T a2) const volatile { return t | a0 | a1 | a2; }
+    T const_volatile_member_func4(T a0, T a1, T a2, T a3) const volatile { return t | a0 | a1 | a2 | a3; }
+    T const_volatile_member_func5(T a0, T a1, T a2, T a3, T a4) const volatile { return t | a0 | a1 | a2 | a3 | a4; }
+};
+
+// bound functions
+template <typename T>
+T bound_func0(Thing<T> *t) { return t->t; }
+template <typename T>
+T bound_func1(Thing<T> *t, T a0) { return t->t | a0; }
+template <typename T>
+T bound_func2(Thing<T> *t, T a0, T a1) { return t->t | a0 | a1; }
+template <typename T>
+T bound_func3(Thing<T> *t, T a0, T a1, T a2) { return t->t | a0 | a1 | a2; }
+template <typename T>
+T bound_func4(Thing<T> *t, T a0, T a1, T a2, T a3) { return t->t | a0 | a1 | a2 | a3; }
+template <typename T>
+T bound_func5(Thing<T> *t, T a0, T a1, T a2, T a3, T a4) { return t->t | a0 | a1 | a2 | a3 | a4; }
+
+// const bound functions
+template <typename T>
+T const_func0(const Thing<T> *t) { return t->t; }
+template <typename T>
+T const_func1(const Thing<T> *t, T a0) { return t->t | a0; }
+template <typename T>
+T const_func2(const Thing<T> *t, T a0, T a1) { return t->t | a0 | a1; }
+template <typename T>
+T const_func3(const Thing<T> *t, T a0, T a1, T a2) { return t->t | a0 | a1 | a2; }
+template <typename T>
+T const_func4(const Thing<T> *t, T a0, T a1, T a2, T a3) { return t->t | a0 | a1 | a2 | a3; }
+template <typename T>
+T const_func5(const Thing<T> *t, T a0, T a1, T a2, T a3, T a4) { return t->t | a0 | a1 | a2 | a3 | a4; }
+
+// volatile bound functions
+template <typename T>
+T volatile_func0(volatile Thing<T> *t) { return t->t; }
+template <typename T>
+T volatile_func1(volatile Thing<T> *t, T a0) { return t->t | a0; }
+template <typename T>
+T volatile_func2(volatile Thing<T> *t, T a0, T a1) { return t->t | a0 | a1; }
+template <typename T>
+T volatile_func3(volatile Thing<T> *t, T a0, T a1, T a2) { return t->t | a0 | a1 | a2; }
+template <typename T>
+T volatile_func4(volatile Thing<T> *t, T a0, T a1, T a2, T a3) { return t->t | a0 | a1 | a2 | a3; }
+template <typename T>
+T volatile_func5(volatile Thing<T> *t, T a0, T a1, T a2, T a3, T a4) { return t->t | a0 | a1 | a2 | a3 | a4; }
+
+// const volatile bound functions
+template <typename T>
+T const_volatile_func0(const volatile Thing<T> *t) { return t->t; }
+template <typename T>
+T const_volatile_func1(const volatile Thing<T> *t, T a0) { return t->t | a0; }
+template <typename T>
+T const_volatile_func2(const volatile Thing<T> *t, T a0, T a1) { return t->t | a0 | a1; }
+template <typename T>
+T const_volatile_func3(const volatile Thing<T> *t, T a0, T a1, T a2) { return t->t | a0 | a1 | a2; }
+template <typename T>
+T const_volatile_func4(const volatile Thing<T> *t, T a0, T a1, T a2, T a3) { return t->t | a0 | a1 | a2 | a3; }
+template <typename T>
+T const_volatile_func5(const volatile Thing<T> *t, T a0, T a1, T a2, T a3, T a4) { return t->t | a0 | a1 | a2 | a3 | a4; }
+
+
+// function call and result verification
+template <typename T>
+struct Verifier {
+    static void verify0(Callback<T()> func) {
+        T result = func();
+        TEST_ASSERT_EQUAL(result, 0x00);
+    }
+
+    template <typename O, typename M>
+    static void verify0(O *obj, M method) {
+        Callback<T()> func(obj, method);
+        T result = func();
+        TEST_ASSERT_EQUAL(result, 0x80);
+    }
+
+    static void verify1(Callback<T(T)> func) {
+        T result = func((1 << 0));
+        TEST_ASSERT_EQUAL(result, 0x00 | (1 << 0));
+    }
+
+    template <typename O, typename M>
+    static void verify1(O *obj, M method) {
+        Callback<T(T)> func(obj, method);
+        T result = func((1 << 0));
+        TEST_ASSERT_EQUAL(result, 0x80 | (1 << 0));
+    }
+
+    static void verify2(Callback<T(T, T)> func) {
+        T result = func((1 << 0), (1 << 1));
+        TEST_ASSERT_EQUAL(result, 0x00 | (1 << 0) | (1 << 1));
+    }
+
+    template <typename O, typename M>
+    static void verify2(O *obj, M method) {
+        Callback<T(T, T)> func(obj, method);
+        T result = func((1 << 0), (1 << 1));
+        TEST_ASSERT_EQUAL(result, 0x80 | (1 << 0) | (1 << 1));
+    }
+
+    static void verify3(Callback<T(T, T, T)> func) {
+        T result = func((1 << 0), (1 << 1), (1 << 2));
+        TEST_ASSERT_EQUAL(result, 0x00 | (1 << 0) | (1 << 1) | (1 << 2));
+    }
+
+    template <typename O, typename M>
+    static void verify3(O *obj, M method) {
+        Callback<T(T, T, T)> func(obj, method);
+        T result = func((1 << 0), (1 << 1), (1 << 2));
+        TEST_ASSERT_EQUAL(result, 0x80 | (1 << 0) | (1 << 1) | (1 << 2));
+    }
+
+    static void verify4(Callback<T(T, T, T, T)> func) {
+        T result = func((1 << 0), (1 << 1), (1 << 2), (1 << 3));
+        TEST_ASSERT_EQUAL(result, 0x00 | (1 << 0) | (1 << 1) | (1 << 2) | (1 << 3));
+    }
+
+    template <typename O, typename M>
+    static void verify4(O *obj, M method) {
+        Callback<T(T, T, T, T)> func(obj, method);
+        T result = func((1 << 0), (1 << 1), (1 << 2), (1 << 3));
+        TEST_ASSERT_EQUAL(result, 0x80 | (1 << 0) | (1 << 1) | (1 << 2) | (1 << 3));
+    }
+
+    static void verify5(Callback<T(T, T, T, T, T)> func) {
+        T result = func((1 << 0), (1 << 1), (1 << 2), (1 << 3), (1 << 4));
+        TEST_ASSERT_EQUAL(result, 0x00 | (1 << 0) | (1 << 1) | (1 << 2) | (1 << 3) | (1 << 4));
+    }
+
+    template <typename O, typename M>
+    static void verify5(O *obj, M method) {
+        Callback<T(T, T, T, T, T)> func(obj, method);
+        T result = func((1 << 0), (1 << 1), (1 << 2), (1 << 3), (1 << 4));
+        TEST_ASSERT_EQUAL(result, 0x80 | (1 << 0) | (1 << 1) | (1 << 2) | (1 << 3) | (1 << 4));
+    }
+};
+
+
+// test dispatch
+template <typename T>
+void test_dispatch0() {
+    Thing<T> thing;
+    Verifier<T>::verify0(static_func0<T>);
+    Verifier<T>::verify0(&thing, &Thing<T>::member_func0);
+    Verifier<T>::verify0((const Thing<T>*)&thing, &Thing<T>::const_member_func0);
+    Verifier<T>::verify0((volatile Thing<T>*)&thing, &Thing<T>::volatile_member_func0);
+    Verifier<T>::verify0((const volatile Thing<T>*)&thing, &Thing<T>::const_volatile_member_func0);
+    Verifier<T>::verify0(&thing, &bound_func0<T>);
+    Verifier<T>::verify0((const Thing<T>*)&thing, &const_func0<T>);
+    Verifier<T>::verify0((volatile Thing<T>*)&thing, &volatile_func0<T>);
+    Verifier<T>::verify0((const volatile Thing<T>*)&thing, &const_volatile_func0<T>);
+    Verifier<T>::verify0(callback(static_func0<T>));
+
+    Callback<T()> cb(static_func0);
+    Verifier<T>::verify0(cb);
+    cb = static_func0;
+    Verifier<T>::verify0(cb);
+    cb.attach(&thing, &bound_func0<T>);
+    Verifier<T>::verify0(&cb, &Callback<T()>::call);
+    Verifier<T>::verify0((void*)&cb, &Callback<T()>::thunk);
+}
+
+template <typename T>
+void test_dispatch1() {
+    Thing<T> thing;
+    Verifier<T>::verify1(static_func1<T>);
+    Verifier<T>::verify1(&thing, &Thing<T>::member_func1);
+    Verifier<T>::verify1((const Thing<T>*)&thing, &Thing<T>::const_member_func1);
+    Verifier<T>::verify1((volatile Thing<T>*)&thing, &Thing<T>::volatile_member_func1);
+    Verifier<T>::verify1((const volatile Thing<T>*)&thing, &Thing<T>::const_volatile_member_func1);
+    Verifier<T>::verify1(&thing, &bound_func1<T>);
+    Verifier<T>::verify1((const Thing<T>*)&thing, &const_func1<T>);
+    Verifier<T>::verify1((volatile Thing<T>*)&thing, &volatile_func1<T>);
+    Verifier<T>::verify1((const volatile Thing<T>*)&thing, &const_volatile_func1<T>);
+    Verifier<T>::verify1(callback(static_func1<T>));
+
+    Callback<T(T)> cb(static_func1);
+    Verifier<T>::verify1(cb);
+    cb = static_func1;
+    Verifier<T>::verify1(cb);
+    cb.attach(&thing, &bound_func1<T>);
+    Verifier<T>::verify1(&cb, &Callback<T(T)>::call);
+    Verifier<T>::verify1((void*)&cb, &Callback<T(T)>::thunk);
+}
+
+template <typename T>
+void test_dispatch2() {
+    Thing<T> thing;
+    Verifier<T>::verify2(static_func2<T>);
+    Verifier<T>::verify2(&thing, &Thing<T>::member_func2);
+    Verifier<T>::verify2((const Thing<T>*)&thing, &Thing<T>::const_member_func2);
+    Verifier<T>::verify2((volatile Thing<T>*)&thing, &Thing<T>::volatile_member_func2);
+    Verifier<T>::verify2((const volatile Thing<T>*)&thing, &Thing<T>::const_volatile_member_func2);
+    Verifier<T>::verify2(&thing, &bound_func2<T>);
+    Verifier<T>::verify2((const Thing<T>*)&thing, &const_func2<T>);
+    Verifier<T>::verify2((volatile Thing<T>*)&thing, &volatile_func2<T>);
+    Verifier<T>::verify2((const volatile Thing<T>*)&thing, &const_volatile_func2<T>);
+    Verifier<T>::verify2(callback(static_func2<T>));
+
+    Callback<T(T, T)> cb(static_func2);
+    Verifier<T>::verify2(cb);
+    cb = static_func2;
+    Verifier<T>::verify2(cb);
+    cb.attach(&thing, &bound_func2<T>);
+    Verifier<T>::verify2(&cb, &Callback<T(T, T)>::call);
+    Verifier<T>::verify2((void*)&cb, &Callback<T(T, T)>::thunk);
+}
+
+template <typename T>
+void test_dispatch3() {
+    Thing<T> thing;
+    Verifier<T>::verify3(static_func3<T>);
+    Verifier<T>::verify3(&thing, &Thing<T>::member_func3);
+    Verifier<T>::verify3((const Thing<T>*)&thing, &Thing<T>::const_member_func3);
+    Verifier<T>::verify3((volatile Thing<T>*)&thing, &Thing<T>::volatile_member_func3);
+    Verifier<T>::verify3((const volatile Thing<T>*)&thing, &Thing<T>::const_volatile_member_func3);
+    Verifier<T>::verify3(&thing, &bound_func3<T>);
+    Verifier<T>::verify3((const Thing<T>*)&thing, &const_func3<T>);
+    Verifier<T>::verify3((volatile Thing<T>*)&thing, &volatile_func3<T>);
+    Verifier<T>::verify3((const volatile Thing<T>*)&thing, &const_volatile_func3<T>);
+    Verifier<T>::verify3(callback(static_func3<T>));
+
+    Callback<T(T, T, T)> cb(static_func3);
+    Verifier<T>::verify3(cb);
+    cb = static_func3;
+    Verifier<T>::verify3(cb);
+    cb.attach(&thing, &bound_func3<T>);
+    Verifier<T>::verify3(&cb, &Callback<T(T, T, T)>::call);
+    Verifier<T>::verify3((void*)&cb, &Callback<T(T, T, T)>::thunk);
+}
+
+template <typename T>
+void test_dispatch4() {
+    Thing<T> thing;
+    Verifier<T>::verify4(static_func4<T>);
+    Verifier<T>::verify4(&thing, &Thing<T>::member_func4);
+    Verifier<T>::verify4((const Thing<T>*)&thing, &Thing<T>::const_member_func4);
+    Verifier<T>::verify4((volatile Thing<T>*)&thing, &Thing<T>::volatile_member_func4);
+    Verifier<T>::verify4((const volatile Thing<T>*)&thing, &Thing<T>::const_volatile_member_func4);
+    Verifier<T>::verify4(&thing, &bound_func4<T>);
+    Verifier<T>::verify4((const Thing<T>*)&thing, &const_func4<T>);
+    Verifier<T>::verify4((volatile Thing<T>*)&thing, &volatile_func4<T>);
+    Verifier<T>::verify4((const volatile Thing<T>*)&thing, &const_volatile_func4<T>);
+    Verifier<T>::verify4(callback(static_func4<T>));
+
+    Callback<T(T, T, T, T)> cb(static_func4);
+    Verifier<T>::verify4(cb);
+    cb = static_func4;
+    Verifier<T>::verify4(cb);
+    cb.attach(&thing, &bound_func4<T>);
+    Verifier<T>::verify4(&cb, &Callback<T(T, T, T, T)>::call);
+    Verifier<T>::verify4((void*)&cb, &Callback<T(T, T, T, T)>::thunk);
+}
+
+template <typename T>
+void test_dispatch5() {
+    Thing<T> thing;
+    Verifier<T>::verify5(static_func5<T>);
+    Verifier<T>::verify5(&thing, &Thing<T>::member_func5);
+    Verifier<T>::verify5((const Thing<T>*)&thing, &Thing<T>::const_member_func5);
+    Verifier<T>::verify5((volatile Thing<T>*)&thing, &Thing<T>::volatile_member_func5);
+    Verifier<T>::verify5((const volatile Thing<T>*)&thing, &Thing<T>::const_volatile_member_func5);
+    Verifier<T>::verify5(&thing, &bound_func5<T>);
+    Verifier<T>::verify5((const Thing<T>*)&thing, &const_func5<T>);
+    Verifier<T>::verify5((volatile Thing<T>*)&thing, &volatile_func5<T>);
+    Verifier<T>::verify5((const volatile Thing<T>*)&thing, &const_volatile_func5<T>);
+    Verifier<T>::verify5(callback(static_func5<T>));
+
+    Callback<T(T, T, T, T, T)> cb(static_func5);
+    Verifier<T>::verify5(cb);
+    cb = static_func5;
+    Verifier<T>::verify5(cb);
+    cb.attach(&thing, &bound_func5<T>);
+    Verifier<T>::verify5(&cb, &Callback<T(T, T, T, T, T)>::call);
+    Verifier<T>::verify5((void*)&cb, &Callback<T(T, T, T, T, T)>::thunk);
+}
+
+
+// Test setup
+utest::v1::status_t test_setup(const size_t number_of_cases) {
+    GREENTEA_SETUP(10, "default_auto");
+    return verbose_test_setup_handler(number_of_cases);
+}
+
+Case cases[] = {
+    Case("Testing callbacks with 0 ints", test_dispatch0<int>),
+    Case("Testing callbacks with 1 ints", test_dispatch1<int>),
+    Case("Testing callbacks with 2 ints", test_dispatch2<int>),
+    Case("Testing callbacks with 3 ints", test_dispatch3<int>),
+    Case("Testing callbacks with 4 ints", test_dispatch4<int>),
+    Case("Testing callbacks with 5 ints", test_dispatch5<int>),
+};
+
+Specification specification(test_setup, cases);
+
+int main() {
+    return !Harness::run(specification);
+}
diff --git a/TESTS/mbed_functional/callback_big/main.cpp b/TESTS/mbed_functional/callback_big/main.cpp
new file mode 100644
index 0000000000..47630a3f21
--- /dev/null
+++ b/TESTS/mbed_functional/callback_big/main.cpp
@@ -0,0 +1,351 @@
+#include "mbed.h"
+#include "greentea-client/test_env.h"
+#include "unity.h"
+#include "utest.h"
+
+using namespace utest::v1;
+
+
+// static functions
+template <typename T>
+T static_func0() { return 0; }
+template <typename T>
+T static_func1(T a0) { return 0 | a0; }
+template <typename T>
+T static_func2(T a0, T a1) { return 0 | a0 | a1; }
+template <typename T>
+T static_func3(T a0, T a1, T a2) { return 0 | a0 | a1 | a2; }
+template <typename T>
+T static_func4(T a0, T a1, T a2, T a3) { return 0 | a0 | a1 | a2 | a3; }
+template <typename T>
+T static_func5(T a0, T a1, T a2, T a3, T a4) { return 0 | a0 | a1 | a2 | a3 | a4; }
+
+// class functions
+template <typename T>
+struct Thing {
+    T t;
+    Thing() : t(0x80) {}
+
+    T member_func0() { return t; }
+    T member_func1(T a0) { return t | a0; }
+    T member_func2(T a0, T a1) { return t | a0 | a1; }
+    T member_func3(T a0, T a1, T a2) { return t | a0 | a1 | a2; }
+    T member_func4(T a0, T a1, T a2, T a3) { return t | a0 | a1 | a2 | a3; }
+    T member_func5(T a0, T a1, T a2, T a3, T a4) { return t | a0 | a1 | a2 | a3 | a4; }
+
+    T const_member_func0() const { return t; }
+    T const_member_func1(T a0) const { return t | a0; }
+    T const_member_func2(T a0, T a1) const { return t | a0 | a1; }
+    T const_member_func3(T a0, T a1, T a2) const { return t | a0 | a1 | a2; }
+    T const_member_func4(T a0, T a1, T a2, T a3) const { return t | a0 | a1 | a2 | a3; }
+    T const_member_func5(T a0, T a1, T a2, T a3, T a4) const { return t | a0 | a1 | a2 | a3 | a4; }
+
+    T volatile_member_func0() volatile { return t; }
+    T volatile_member_func1(T a0) volatile { return t | a0; }
+    T volatile_member_func2(T a0, T a1) volatile { return t | a0 | a1; }
+    T volatile_member_func3(T a0, T a1, T a2) volatile { return t | a0 | a1 | a2; }
+    T volatile_member_func4(T a0, T a1, T a2, T a3) volatile { return t | a0 | a1 | a2 | a3; }
+    T volatile_member_func5(T a0, T a1, T a2, T a3, T a4) volatile { return t | a0 | a1 | a2 | a3 | a4; }
+
+    T const_volatile_member_func0() const volatile { return t; }
+    T const_volatile_member_func1(T a0) const volatile { return t | a0; }
+    T const_volatile_member_func2(T a0, T a1) const volatile { return t | a0 | a1; }
+    T const_volatile_member_func3(T a0, T a1, T a2) const volatile { return t | a0 | a1 | a2; }
+    T const_volatile_member_func4(T a0, T a1, T a2, T a3) const volatile { return t | a0 | a1 | a2 | a3; }
+    T const_volatile_member_func5(T a0, T a1, T a2, T a3, T a4) const volatile { return t | a0 | a1 | a2 | a3 | a4; }
+};
+
+// bound functions
+template <typename T>
+T bound_func0(Thing<T> *t) { return t->t; }
+template <typename T>
+T bound_func1(Thing<T> *t, T a0) { return t->t | a0; }
+template <typename T>
+T bound_func2(Thing<T> *t, T a0, T a1) { return t->t | a0 | a1; }
+template <typename T>
+T bound_func3(Thing<T> *t, T a0, T a1, T a2) { return t->t | a0 | a1 | a2; }
+template <typename T>
+T bound_func4(Thing<T> *t, T a0, T a1, T a2, T a3) { return t->t | a0 | a1 | a2 | a3; }
+template <typename T>
+T bound_func5(Thing<T> *t, T a0, T a1, T a2, T a3, T a4) { return t->t | a0 | a1 | a2 | a3 | a4; }
+
+// const bound functions
+template <typename T>
+T const_func0(const Thing<T> *t) { return t->t; }
+template <typename T>
+T const_func1(const Thing<T> *t, T a0) { return t->t | a0; }
+template <typename T>
+T const_func2(const Thing<T> *t, T a0, T a1) { return t->t | a0 | a1; }
+template <typename T>
+T const_func3(const Thing<T> *t, T a0, T a1, T a2) { return t->t | a0 | a1 | a2; }
+template <typename T>
+T const_func4(const Thing<T> *t, T a0, T a1, T a2, T a3) { return t->t | a0 | a1 | a2 | a3; }
+template <typename T>
+T const_func5(const Thing<T> *t, T a0, T a1, T a2, T a3, T a4) { return t->t | a0 | a1 | a2 | a3 | a4; }
+
+// volatile bound functions
+template <typename T>
+T volatile_func0(volatile Thing<T> *t) { return t->t; }
+template <typename T>
+T volatile_func1(volatile Thing<T> *t, T a0) { return t->t | a0; }
+template <typename T>
+T volatile_func2(volatile Thing<T> *t, T a0, T a1) { return t->t | a0 | a1; }
+template <typename T>
+T volatile_func3(volatile Thing<T> *t, T a0, T a1, T a2) { return t->t | a0 | a1 | a2; }
+template <typename T>
+T volatile_func4(volatile Thing<T> *t, T a0, T a1, T a2, T a3) { return t->t | a0 | a1 | a2 | a3; }
+template <typename T>
+T volatile_func5(volatile Thing<T> *t, T a0, T a1, T a2, T a3, T a4) { return t->t | a0 | a1 | a2 | a3 | a4; }
+
+// const volatile bound functions
+template <typename T>
+T const_volatile_func0(const volatile Thing<T> *t) { return t->t; }
+template <typename T>
+T const_volatile_func1(const volatile Thing<T> *t, T a0) { return t->t | a0; }
+template <typename T>
+T const_volatile_func2(const volatile Thing<T> *t, T a0, T a1) { return t->t | a0 | a1; }
+template <typename T>
+T const_volatile_func3(const volatile Thing<T> *t, T a0, T a1, T a2) { return t->t | a0 | a1 | a2; }
+template <typename T>
+T const_volatile_func4(const volatile Thing<T> *t, T a0, T a1, T a2, T a3) { return t->t | a0 | a1 | a2 | a3; }
+template <typename T>
+T const_volatile_func5(const volatile Thing<T> *t, T a0, T a1, T a2, T a3, T a4) { return t->t | a0 | a1 | a2 | a3 | a4; }
+
+
+// function call and result verification
+template <typename T>
+struct Verifier {
+    static void verify0(Callback<T()> func) {
+        T result = func();
+        TEST_ASSERT_EQUAL(result, 0x00);
+    }
+
+    template <typename O, typename M>
+    static void verify0(O *obj, M method) {
+        Callback<T()> func(obj, method);
+        T result = func();
+        TEST_ASSERT_EQUAL(result, 0x80);
+    }
+
+    static void verify1(Callback<T(T)> func) {
+        T result = func((1 << 0));
+        TEST_ASSERT_EQUAL(result, 0x00 | (1 << 0));
+    }
+
+    template <typename O, typename M>
+    static void verify1(O *obj, M method) {
+        Callback<T(T)> func(obj, method);
+        T result = func((1 << 0));
+        TEST_ASSERT_EQUAL(result, 0x80 | (1 << 0));
+    }
+
+    static void verify2(Callback<T(T, T)> func) {
+        T result = func((1 << 0), (1 << 1));
+        TEST_ASSERT_EQUAL(result, 0x00 | (1 << 0) | (1 << 1));
+    }
+
+    template <typename O, typename M>
+    static void verify2(O *obj, M method) {
+        Callback<T(T, T)> func(obj, method);
+        T result = func((1 << 0), (1 << 1));
+        TEST_ASSERT_EQUAL(result, 0x80 | (1 << 0) | (1 << 1));
+    }
+
+    static void verify3(Callback<T(T, T, T)> func) {
+        T result = func((1 << 0), (1 << 1), (1 << 2));
+        TEST_ASSERT_EQUAL(result, 0x00 | (1 << 0) | (1 << 1) | (1 << 2));
+    }
+
+    template <typename O, typename M>
+    static void verify3(O *obj, M method) {
+        Callback<T(T, T, T)> func(obj, method);
+        T result = func((1 << 0), (1 << 1), (1 << 2));
+        TEST_ASSERT_EQUAL(result, 0x80 | (1 << 0) | (1 << 1) | (1 << 2));
+    }
+
+    static void verify4(Callback<T(T, T, T, T)> func) {
+        T result = func((1 << 0), (1 << 1), (1 << 2), (1 << 3));
+        TEST_ASSERT_EQUAL(result, 0x00 | (1 << 0) | (1 << 1) | (1 << 2) | (1 << 3));
+    }
+
+    template <typename O, typename M>
+    static void verify4(O *obj, M method) {
+        Callback<T(T, T, T, T)> func(obj, method);
+        T result = func((1 << 0), (1 << 1), (1 << 2), (1 << 3));
+        TEST_ASSERT_EQUAL(result, 0x80 | (1 << 0) | (1 << 1) | (1 << 2) | (1 << 3));
+    }
+
+    static void verify5(Callback<T(T, T, T, T, T)> func) {
+        T result = func((1 << 0), (1 << 1), (1 << 2), (1 << 3), (1 << 4));
+        TEST_ASSERT_EQUAL(result, 0x00 | (1 << 0) | (1 << 1) | (1 << 2) | (1 << 3) | (1 << 4));
+    }
+
+    template <typename O, typename M>
+    static void verify5(O *obj, M method) {
+        Callback<T(T, T, T, T, T)> func(obj, method);
+        T result = func((1 << 0), (1 << 1), (1 << 2), (1 << 3), (1 << 4));
+        TEST_ASSERT_EQUAL(result, 0x80 | (1 << 0) | (1 << 1) | (1 << 2) | (1 << 3) | (1 << 4));
+    }
+};
+
+
+// test dispatch
+template <typename T>
+void test_dispatch0() {
+    Thing<T> thing;
+    Verifier<T>::verify0(static_func0<T>);
+    Verifier<T>::verify0(&thing, &Thing<T>::member_func0);
+    Verifier<T>::verify0((const Thing<T>*)&thing, &Thing<T>::const_member_func0);
+    Verifier<T>::verify0((volatile Thing<T>*)&thing, &Thing<T>::volatile_member_func0);
+    Verifier<T>::verify0((const volatile Thing<T>*)&thing, &Thing<T>::const_volatile_member_func0);
+    Verifier<T>::verify0(&thing, &bound_func0<T>);
+    Verifier<T>::verify0((const Thing<T>*)&thing, &const_func0<T>);
+    Verifier<T>::verify0((volatile Thing<T>*)&thing, &volatile_func0<T>);
+    Verifier<T>::verify0((const volatile Thing<T>*)&thing, &const_volatile_func0<T>);
+    Verifier<T>::verify0(callback(static_func0<T>));
+
+    Callback<T()> cb(static_func0);
+    Verifier<T>::verify0(cb);
+    cb = static_func0;
+    Verifier<T>::verify0(cb);
+    cb.attach(&thing, &bound_func0<T>);
+    Verifier<T>::verify0(&cb, &Callback<T()>::call);
+    Verifier<T>::verify0((void*)&cb, &Callback<T()>::thunk);
+}
+
+template <typename T>
+void test_dispatch1() {
+    Thing<T> thing;
+    Verifier<T>::verify1(static_func1<T>);
+    Verifier<T>::verify1(&thing, &Thing<T>::member_func1);
+    Verifier<T>::verify1((const Thing<T>*)&thing, &Thing<T>::const_member_func1);
+    Verifier<T>::verify1((volatile Thing<T>*)&thing, &Thing<T>::volatile_member_func1);
+    Verifier<T>::verify1((const volatile Thing<T>*)&thing, &Thing<T>::const_volatile_member_func1);
+    Verifier<T>::verify1(&thing, &bound_func1<T>);
+    Verifier<T>::verify1((const Thing<T>*)&thing, &const_func1<T>);
+    Verifier<T>::verify1((volatile Thing<T>*)&thing, &volatile_func1<T>);
+    Verifier<T>::verify1((const volatile Thing<T>*)&thing, &const_volatile_func1<T>);
+    Verifier<T>::verify1(callback(static_func1<T>));
+
+    Callback<T(T)> cb(static_func1);
+    Verifier<T>::verify1(cb);
+    cb = static_func1;
+    Verifier<T>::verify1(cb);
+    cb.attach(&thing, &bound_func1<T>);
+    Verifier<T>::verify1(&cb, &Callback<T(T)>::call);
+    Verifier<T>::verify1((void*)&cb, &Callback<T(T)>::thunk);
+}
+
+template <typename T>
+void test_dispatch2() {
+    Thing<T> thing;
+    Verifier<T>::verify2(static_func2<T>);
+    Verifier<T>::verify2(&thing, &Thing<T>::member_func2);
+    Verifier<T>::verify2((const Thing<T>*)&thing, &Thing<T>::const_member_func2);
+    Verifier<T>::verify2((volatile Thing<T>*)&thing, &Thing<T>::volatile_member_func2);
+    Verifier<T>::verify2((const volatile Thing<T>*)&thing, &Thing<T>::const_volatile_member_func2);
+    Verifier<T>::verify2(&thing, &bound_func2<T>);
+    Verifier<T>::verify2((const Thing<T>*)&thing, &const_func2<T>);
+    Verifier<T>::verify2((volatile Thing<T>*)&thing, &volatile_func2<T>);
+    Verifier<T>::verify2((const volatile Thing<T>*)&thing, &const_volatile_func2<T>);
+    Verifier<T>::verify2(callback(static_func2<T>));
+
+    Callback<T(T, T)> cb(static_func2);
+    Verifier<T>::verify2(cb);
+    cb = static_func2;
+    Verifier<T>::verify2(cb);
+    cb.attach(&thing, &bound_func2<T>);
+    Verifier<T>::verify2(&cb, &Callback<T(T, T)>::call);
+    Verifier<T>::verify2((void*)&cb, &Callback<T(T, T)>::thunk);
+}
+
+template <typename T>
+void test_dispatch3() {
+    Thing<T> thing;
+    Verifier<T>::verify3(static_func3<T>);
+    Verifier<T>::verify3(&thing, &Thing<T>::member_func3);
+    Verifier<T>::verify3((const Thing<T>*)&thing, &Thing<T>::const_member_func3);
+    Verifier<T>::verify3((volatile Thing<T>*)&thing, &Thing<T>::volatile_member_func3);
+    Verifier<T>::verify3((const volatile Thing<T>*)&thing, &Thing<T>::const_volatile_member_func3);
+    Verifier<T>::verify3(&thing, &bound_func3<T>);
+    Verifier<T>::verify3((const Thing<T>*)&thing, &const_func3<T>);
+    Verifier<T>::verify3((volatile Thing<T>*)&thing, &volatile_func3<T>);
+    Verifier<T>::verify3((const volatile Thing<T>*)&thing, &const_volatile_func3<T>);
+    Verifier<T>::verify3(callback(static_func3<T>));
+
+    Callback<T(T, T, T)> cb(static_func3);
+    Verifier<T>::verify3(cb);
+    cb = static_func3;
+    Verifier<T>::verify3(cb);
+    cb.attach(&thing, &bound_func3<T>);
+    Verifier<T>::verify3(&cb, &Callback<T(T, T, T)>::call);
+    Verifier<T>::verify3((void*)&cb, &Callback<T(T, T, T)>::thunk);
+}
+
+template <typename T>
+void test_dispatch4() {
+    Thing<T> thing;
+    Verifier<T>::verify4(static_func4<T>);
+    Verifier<T>::verify4(&thing, &Thing<T>::member_func4);
+    Verifier<T>::verify4((const Thing<T>*)&thing, &Thing<T>::const_member_func4);
+    Verifier<T>::verify4((volatile Thing<T>*)&thing, &Thing<T>::volatile_member_func4);
+    Verifier<T>::verify4((const volatile Thing<T>*)&thing, &Thing<T>::const_volatile_member_func4);
+    Verifier<T>::verify4(&thing, &bound_func4<T>);
+    Verifier<T>::verify4((const Thing<T>*)&thing, &const_func4<T>);
+    Verifier<T>::verify4((volatile Thing<T>*)&thing, &volatile_func4<T>);
+    Verifier<T>::verify4((const volatile Thing<T>*)&thing, &const_volatile_func4<T>);
+    Verifier<T>::verify4(callback(static_func4<T>));
+
+    Callback<T(T, T, T, T)> cb(static_func4);
+    Verifier<T>::verify4(cb);
+    cb = static_func4;
+    Verifier<T>::verify4(cb);
+    cb.attach(&thing, &bound_func4<T>);
+    Verifier<T>::verify4(&cb, &Callback<T(T, T, T, T)>::call);
+    Verifier<T>::verify4((void*)&cb, &Callback<T(T, T, T, T)>::thunk);
+}
+
+template <typename T>
+void test_dispatch5() {
+    Thing<T> thing;
+    Verifier<T>::verify5(static_func5<T>);
+    Verifier<T>::verify5(&thing, &Thing<T>::member_func5);
+    Verifier<T>::verify5((const Thing<T>*)&thing, &Thing<T>::const_member_func5);
+    Verifier<T>::verify5((volatile Thing<T>*)&thing, &Thing<T>::volatile_member_func5);
+    Verifier<T>::verify5((const volatile Thing<T>*)&thing, &Thing<T>::const_volatile_member_func5);
+    Verifier<T>::verify5(&thing, &bound_func5<T>);
+    Verifier<T>::verify5((const Thing<T>*)&thing, &const_func5<T>);
+    Verifier<T>::verify5((volatile Thing<T>*)&thing, &volatile_func5<T>);
+    Verifier<T>::verify5((const volatile Thing<T>*)&thing, &const_volatile_func5<T>);
+    Verifier<T>::verify5(callback(static_func5<T>));
+
+    Callback<T(T, T, T, T, T)> cb(static_func5);
+    Verifier<T>::verify5(cb);
+    cb = static_func5;
+    Verifier<T>::verify5(cb);
+    cb.attach(&thing, &bound_func5<T>);
+    Verifier<T>::verify5(&cb, &Callback<T(T, T, T, T, T)>::call);
+    Verifier<T>::verify5((void*)&cb, &Callback<T(T, T, T, T, T)>::thunk);
+}
+
+
+// Test setup
+utest::v1::status_t test_setup(const size_t number_of_cases) {
+    GREENTEA_SETUP(10, "default_auto");
+    return verbose_test_setup_handler(number_of_cases);
+}
+
+Case cases[] = {
+    Case("Testing callbacks with 0 uint64s", test_dispatch0<uint64_t>),
+    Case("Testing callbacks with 1 uint64s", test_dispatch1<uint64_t>),
+    Case("Testing callbacks with 2 uint64s", test_dispatch2<uint64_t>),
+    Case("Testing callbacks with 3 uint64s", test_dispatch3<uint64_t>),
+    Case("Testing callbacks with 4 uint64s", test_dispatch4<uint64_t>),
+    Case("Testing callbacks with 5 uint64s", test_dispatch5<uint64_t>),
+};
+
+Specification specification(test_setup, cases);
+
+int main() {
+    return !Harness::run(specification);
+}
diff --git a/TESTS/mbed_drivers/callback/main.cpp b/TESTS/mbed_functional/callback_small/main.cpp
similarity index 91%
rename from TESTS/mbed_drivers/callback/main.cpp
rename to TESTS/mbed_functional/callback_small/main.cpp
index 403968a039..e5fa15b4b6 100644
--- a/TESTS/mbed_drivers/callback/main.cpp
+++ b/TESTS/mbed_functional/callback_small/main.cpp
@@ -328,22 +328,6 @@ void test_dispatch5() {
     Verifier<T>::verify5((void*)&cb, &Callback<T(T, T, T, T, T)>::thunk);
 }
 
-template <typename T>
-void test_fparg1() {
-    Thing<T> thing;
-    FunctionPointerArg1<T,T> fp(static_func1<T>);
-    Verifier<T>::verify1(fp);
-    Verifier<T>::verify1(fp.get_function());
-}
-
-template <typename T>
-void test_fparg0() {
-    Thing<T> thing;
-    FunctionPointerArg1<T,void> fp(static_func0<T>);
-    Verifier<T>::verify0(fp);
-    Verifier<T>::verify0(fp.get_function());
-}
-
 
 // Test setup
 utest::v1::status_t test_setup(const size_t number_of_cases) {
@@ -352,29 +336,12 @@ utest::v1::status_t test_setup(const size_t number_of_cases) {
 }
 
 Case cases[] = {
-    Case("Testing callbacks with 0 ints", test_dispatch0<int>),
-    Case("Testing callbacks with 1 ints", test_dispatch1<int>),
-    Case("Testing callbacks with 2 ints", test_dispatch2<int>),
-    Case("Testing callbacks with 3 ints", test_dispatch3<int>),
-    Case("Testing callbacks with 4 ints", test_dispatch4<int>),
-    Case("Testing callbacks with 5 ints", test_dispatch5<int>),
-
     Case("Testing callbacks with 0 uchars", test_dispatch0<unsigned char>),
     Case("Testing callbacks with 1 uchars", test_dispatch1<unsigned char>),
     Case("Testing callbacks with 2 uchars", test_dispatch2<unsigned char>),
     Case("Testing callbacks with 3 uchars", test_dispatch3<unsigned char>),
     Case("Testing callbacks with 4 uchars", test_dispatch4<unsigned char>),
     Case("Testing callbacks with 5 uchars", test_dispatch5<unsigned char>),
-
-    Case("Testing callbacks with 0 uint64s", test_dispatch0<uint64_t>),
-    Case("Testing callbacks with 1 uint64s", test_dispatch1<uint64_t>),
-    Case("Testing callbacks with 2 uint64s", test_dispatch2<uint64_t>),
-    Case("Testing callbacks with 3 uint64s", test_dispatch3<uint64_t>),
-    Case("Testing callbacks with 4 uint64s", test_dispatch4<uint64_t>),
-    Case("Testing callbacks with 5 uint64s", test_dispatch5<uint64_t>),
-
-    Case("Testing FunctionPointerArg1 compatibility", test_fparg1<int>),
-    Case("Testing FunctionPointer compatibility", test_fparg0<int>),
 };
 
 Specification specification(test_setup, cases);
diff --git a/TESTS/mbed_functional/functionpointer/main.cpp b/TESTS/mbed_functional/functionpointer/main.cpp
new file mode 100644
index 0000000000..7a61dc0abd
--- /dev/null
+++ b/TESTS/mbed_functional/functionpointer/main.cpp
@@ -0,0 +1,225 @@
+#include "mbed.h"
+#include "greentea-client/test_env.h"
+#include "unity.h"
+#include "utest.h"
+
+using namespace utest::v1;
+
+
+// static functions
+template <typename T>
+T static_func0() { return 0; }
+template <typename T>
+T static_func1(T a0) { return 0 | a0; }
+template <typename T>
+T static_func2(T a0, T a1) { return 0 | a0 | a1; }
+template <typename T>
+T static_func3(T a0, T a1, T a2) { return 0 | a0 | a1 | a2; }
+template <typename T>
+T static_func4(T a0, T a1, T a2, T a3) { return 0 | a0 | a1 | a2 | a3; }
+template <typename T>
+T static_func5(T a0, T a1, T a2, T a3, T a4) { return 0 | a0 | a1 | a2 | a3 | a4; }
+
+// class functions
+template <typename T>
+struct Thing {
+    T t;
+    Thing() : t(0x80) {}
+
+    T member_func0() { return t; }
+    T member_func1(T a0) { return t | a0; }
+    T member_func2(T a0, T a1) { return t | a0 | a1; }
+    T member_func3(T a0, T a1, T a2) { return t | a0 | a1 | a2; }
+    T member_func4(T a0, T a1, T a2, T a3) { return t | a0 | a1 | a2 | a3; }
+    T member_func5(T a0, T a1, T a2, T a3, T a4) { return t | a0 | a1 | a2 | a3 | a4; }
+
+    T const_member_func0() const { return t; }
+    T const_member_func1(T a0) const { return t | a0; }
+    T const_member_func2(T a0, T a1) const { return t | a0 | a1; }
+    T const_member_func3(T a0, T a1, T a2) const { return t | a0 | a1 | a2; }
+    T const_member_func4(T a0, T a1, T a2, T a3) const { return t | a0 | a1 | a2 | a3; }
+    T const_member_func5(T a0, T a1, T a2, T a3, T a4) const { return t | a0 | a1 | a2 | a3 | a4; }
+
+    T volatile_member_func0() volatile { return t; }
+    T volatile_member_func1(T a0) volatile { return t | a0; }
+    T volatile_member_func2(T a0, T a1) volatile { return t | a0 | a1; }
+    T volatile_member_func3(T a0, T a1, T a2) volatile { return t | a0 | a1 | a2; }
+    T volatile_member_func4(T a0, T a1, T a2, T a3) volatile { return t | a0 | a1 | a2 | a3; }
+    T volatile_member_func5(T a0, T a1, T a2, T a3, T a4) volatile { return t | a0 | a1 | a2 | a3 | a4; }
+
+    T const_volatile_member_func0() const volatile { return t; }
+    T const_volatile_member_func1(T a0) const volatile { return t | a0; }
+    T const_volatile_member_func2(T a0, T a1) const volatile { return t | a0 | a1; }
+    T const_volatile_member_func3(T a0, T a1, T a2) const volatile { return t | a0 | a1 | a2; }
+    T const_volatile_member_func4(T a0, T a1, T a2, T a3) const volatile { return t | a0 | a1 | a2 | a3; }
+    T const_volatile_member_func5(T a0, T a1, T a2, T a3, T a4) const volatile { return t | a0 | a1 | a2 | a3 | a4; }
+};
+
+// bound functions
+template <typename T>
+T bound_func0(Thing<T> *t) { return t->t; }
+template <typename T>
+T bound_func1(Thing<T> *t, T a0) { return t->t | a0; }
+template <typename T>
+T bound_func2(Thing<T> *t, T a0, T a1) { return t->t | a0 | a1; }
+template <typename T>
+T bound_func3(Thing<T> *t, T a0, T a1, T a2) { return t->t | a0 | a1 | a2; }
+template <typename T>
+T bound_func4(Thing<T> *t, T a0, T a1, T a2, T a3) { return t->t | a0 | a1 | a2 | a3; }
+template <typename T>
+T bound_func5(Thing<T> *t, T a0, T a1, T a2, T a3, T a4) { return t->t | a0 | a1 | a2 | a3 | a4; }
+
+// const bound functions
+template <typename T>
+T const_func0(const Thing<T> *t) { return t->t; }
+template <typename T>
+T const_func1(const Thing<T> *t, T a0) { return t->t | a0; }
+template <typename T>
+T const_func2(const Thing<T> *t, T a0, T a1) { return t->t | a0 | a1; }
+template <typename T>
+T const_func3(const Thing<T> *t, T a0, T a1, T a2) { return t->t | a0 | a1 | a2; }
+template <typename T>
+T const_func4(const Thing<T> *t, T a0, T a1, T a2, T a3) { return t->t | a0 | a1 | a2 | a3; }
+template <typename T>
+T const_func5(const Thing<T> *t, T a0, T a1, T a2, T a3, T a4) { return t->t | a0 | a1 | a2 | a3 | a4; }
+
+// volatile bound functions
+template <typename T>
+T volatile_func0(volatile Thing<T> *t) { return t->t; }
+template <typename T>
+T volatile_func1(volatile Thing<T> *t, T a0) { return t->t | a0; }
+template <typename T>
+T volatile_func2(volatile Thing<T> *t, T a0, T a1) { return t->t | a0 | a1; }
+template <typename T>
+T volatile_func3(volatile Thing<T> *t, T a0, T a1, T a2) { return t->t | a0 | a1 | a2; }
+template <typename T>
+T volatile_func4(volatile Thing<T> *t, T a0, T a1, T a2, T a3) { return t->t | a0 | a1 | a2 | a3; }
+template <typename T>
+T volatile_func5(volatile Thing<T> *t, T a0, T a1, T a2, T a3, T a4) { return t->t | a0 | a1 | a2 | a3 | a4; }
+
+// const volatile bound functions
+template <typename T>
+T const_volatile_func0(const volatile Thing<T> *t) { return t->t; }
+template <typename T>
+T const_volatile_func1(const volatile Thing<T> *t, T a0) { return t->t | a0; }
+template <typename T>
+T const_volatile_func2(const volatile Thing<T> *t, T a0, T a1) { return t->t | a0 | a1; }
+template <typename T>
+T const_volatile_func3(const volatile Thing<T> *t, T a0, T a1, T a2) { return t->t | a0 | a1 | a2; }
+template <typename T>
+T const_volatile_func4(const volatile Thing<T> *t, T a0, T a1, T a2, T a3) { return t->t | a0 | a1 | a2 | a3; }
+template <typename T>
+T const_volatile_func5(const volatile Thing<T> *t, T a0, T a1, T a2, T a3, T a4) { return t->t | a0 | a1 | a2 | a3 | a4; }
+
+
+// function call and result verification
+template <typename T>
+struct Verifier {
+    static void verify0(Callback<T()> func) {
+        T result = func();
+        TEST_ASSERT_EQUAL(result, 0x00);
+    }
+
+    template <typename O, typename M>
+    static void verify0(O *obj, M method) {
+        Callback<T()> func(obj, method);
+        T result = func();
+        TEST_ASSERT_EQUAL(result, 0x80);
+    }
+
+    static void verify1(Callback<T(T)> func) {
+        T result = func((1 << 0));
+        TEST_ASSERT_EQUAL(result, 0x00 | (1 << 0));
+    }
+
+    template <typename O, typename M>
+    static void verify1(O *obj, M method) {
+        Callback<T(T)> func(obj, method);
+        T result = func((1 << 0));
+        TEST_ASSERT_EQUAL(result, 0x80 | (1 << 0));
+    }
+
+    static void verify2(Callback<T(T, T)> func) {
+        T result = func((1 << 0), (1 << 1));
+        TEST_ASSERT_EQUAL(result, 0x00 | (1 << 0) | (1 << 1));
+    }
+
+    template <typename O, typename M>
+    static void verify2(O *obj, M method) {
+        Callback<T(T, T)> func(obj, method);
+        T result = func((1 << 0), (1 << 1));
+        TEST_ASSERT_EQUAL(result, 0x80 | (1 << 0) | (1 << 1));
+    }
+
+    static void verify3(Callback<T(T, T, T)> func) {
+        T result = func((1 << 0), (1 << 1), (1 << 2));
+        TEST_ASSERT_EQUAL(result, 0x00 | (1 << 0) | (1 << 1) | (1 << 2));
+    }
+
+    template <typename O, typename M>
+    static void verify3(O *obj, M method) {
+        Callback<T(T, T, T)> func(obj, method);
+        T result = func((1 << 0), (1 << 1), (1 << 2));
+        TEST_ASSERT_EQUAL(result, 0x80 | (1 << 0) | (1 << 1) | (1 << 2));
+    }
+
+    static void verify4(Callback<T(T, T, T, T)> func) {
+        T result = func((1 << 0), (1 << 1), (1 << 2), (1 << 3));
+        TEST_ASSERT_EQUAL(result, 0x00 | (1 << 0) | (1 << 1) | (1 << 2) | (1 << 3));
+    }
+
+    template <typename O, typename M>
+    static void verify4(O *obj, M method) {
+        Callback<T(T, T, T, T)> func(obj, method);
+        T result = func((1 << 0), (1 << 1), (1 << 2), (1 << 3));
+        TEST_ASSERT_EQUAL(result, 0x80 | (1 << 0) | (1 << 1) | (1 << 2) | (1 << 3));
+    }
+
+    static void verify5(Callback<T(T, T, T, T, T)> func) {
+        T result = func((1 << 0), (1 << 1), (1 << 2), (1 << 3), (1 << 4));
+        TEST_ASSERT_EQUAL(result, 0x00 | (1 << 0) | (1 << 1) | (1 << 2) | (1 << 3) | (1 << 4));
+    }
+
+    template <typename O, typename M>
+    static void verify5(O *obj, M method) {
+        Callback<T(T, T, T, T, T)> func(obj, method);
+        T result = func((1 << 0), (1 << 1), (1 << 2), (1 << 3), (1 << 4));
+        TEST_ASSERT_EQUAL(result, 0x80 | (1 << 0) | (1 << 1) | (1 << 2) | (1 << 3) | (1 << 4));
+    }
+};
+
+
+// test dispatch
+template <typename T>
+void test_fparg1() {
+    Thing<T> thing;
+    FunctionPointerArg1<T,T> fp(static_func1<T>);
+    Verifier<T>::verify1(fp);
+    Verifier<T>::verify1(fp.get_function());
+}
+
+template <typename T>
+void test_fparg0() {
+    Thing<T> thing;
+    FunctionPointerArg1<T,void> fp(static_func0<T>);
+    Verifier<T>::verify0(fp);
+    Verifier<T>::verify0(fp.get_function());
+}
+
+
+// Test setup
+utest::v1::status_t test_setup(const size_t number_of_cases) {
+    GREENTEA_SETUP(10, "default_auto");
+    return verbose_test_setup_handler(number_of_cases);
+}
+
+Case cases[] = {
+    Case("Testing FunctionPointerArg1 compatibility", test_fparg1<int>),
+    Case("Testing FunctionPointer compatibility", test_fparg0<int>),
+};
+
+Specification specification(test_setup, cases);
+
+int main() {
+    return !Harness::run(specification);
+}