Previously, write() was somewhat soft - it only ever made one attempt to
wait for buffer space, so it would take as much data as would fit in the
buffer in one call.
This is not the intent of a POSIX filehandle write. It should try to
send everything if blocking, and only send less if interrupted by a
signal:
- If the O_NONBLOCK flag is clear, write() shall block the calling
thread until the data can be accepted.
- If the O_NONBLOCK flag is set, write() shall not block the thread.
If some data can be written without blocking the thread, write()
shall write what it can and return the number of bytes written.
Otherwise, it shall return -1 and set errno to [EAGAIN].
This "send all" behaviour is of slightly limited usefulness in POSIX, as
you still usually have to worry about the interruption possibility:
- If write() is interrupted by a signal before it writes any data, it
shall return -1 with errno set to [EINTR].
- If write() is interrupted by a signal after it successfully writes
some data, it shall return the number of bytes written.
But as mbed OS does not have the possibility of signal interruption, if we
strengthen write to write everything, we can make applications' lives
easier - they can just do "write(large amount)" confident that it will
all go in one call (if no errors).
So, rework to make multiple writes to the buffer, blocking as necessary,
until all data is written.
This change does not apply to read(), which is correct in only blocking until
some data is available:
- If O_NONBLOCK is set, read() shall return -1 and set errno to [EAGAIN].
- If O_NONBLOCK is clear, read() shall block the calling thread until some
data becomes available.
- The use of the O_NONBLOCK flag has no effect if there is some data
available.
Previously, send() was somewhat soft - it only ever made one send
call to the underlying stack, so it would typically take as much data
as would fit in the buffer, and only block if it was unable to write
anything.
This is not the intent of a POSIX socket/filehandle write. It should try
to send everything if blocking, and only send less if interrupted by a
signal:
- If the O_NONBLOCK flag is clear, write() shall block the calling
thread until the data can be accepted.
- If the O_NONBLOCK flag is set, write() shall not block the thread.
If some data can be written without blocking the thread, write()
shall write what it can and return the number of bytes written.
Otherwise, it shall return -1 and set errno to [EAGAIN].
This "send all" behaviour is of slightly limited usefulness in POSIX, as
you still usually have to worry about the interruption possibility:
- If write() is interrupted by a signal before it writes any data, it
shall return -1 with errno set to [EINTR].
- If write() is interrupted by a signal after it successfully writes
some data, it shall return the number of bytes written.
But as mbed OS does not have the possibility of signal interruption, if we
strengthen send to write everything, we can make applications' lives
easier - they can just do "send(large amount)" confident that it will
all go in one call (if no errors).
So, rework to make multiple sends to the underlying stack, blocking as
necessary, until all data is written.
This change does not apply to recv(), which is correct in only blocking until
some data is available:
- If O_NONBLOCK is set, read() shall return -1 and set errno to [EAGAIN].
- If O_NONBLOCK is clear, read() shall block the calling thread until some
data becomes available.
- The use of the O_NONBLOCK flag has no effect if there is some data
available.
If map file parsing fails then memap_instance is set to None. To
prevent a traceback when parsing fails check if this is None before
trying to access any of its fields.
Remove the condition code around the defines in mbed_retarget.h so
all toolchains use the defined values. Exclude a small subset of
values for GCC since these are in its standard header files.
Defaulted to HeapBlockDevice. Unfortunately this does mean that
by default almost none of the tests are actually capable of running
unless the dut has >512KB or RAM.
The parallel name was incorrect. These tests do not involve mutliple
threads, but rather write to multiple files an in interspersed manner
sequentially.
errno (part of thread local storage) setting caused hardfault with IAR8.x
versions. TLS is not supported, hence using main thread TLS area for
all threads.
Amanda Butler
Vincent Coubard
Kevin Bracey
Deepika
Russ Butler
Jimmy Brisson
Michael Kaplan
Maciej Bocianski
Christopher Haster
gorazd
bcostm
Martin Kojtal
Marko Fabo