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Fix RawSerial when used with ARMCC microlib 

The function vsnprintf does not properly handle a size of zero for
the destination buffer, and will write data to it.  If the buffer is
set to null this will cause a hardfault.  This patch adds a workaround
for this bug by using a buffer of size 1.
pull/1497/head
Russ 2016-01-10 19:01:46 -06:00
parent 8b10c2ae00
commit f8ada507af
1 changed files with 4 additions and 1 deletions
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5
libraries/mbed/common/RawSerial.cpp
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@ -47,7 +47,10 @@ int RawSerial::puts(const char *str) {
int RawSerial::printf(const char *format, ...) {
std::va_list arg;
va_start(arg, format);
int len = vsnprintf(NULL, 0, format, arg);
// ARMCC microlib does not properly handle a size of 0.
// As a workaround supply a dummy buffer with a size of 1.
char dummy_buf[1];
int len = vsnprintf(dummy_buf, sizeof(dummy_buf), format, arg);
if (len < STRING_STACK_LIMIT) {
char temp[STRING_STACK_LIMIT];
vsprintf(temp, format, arg);