9.291 fputc

POSIX specification:
http://www.opengroup.org/onlinepubs/9699919799/functions/fputc.html

Gnulib module: stdio, nonblocking, sigpipe

Portability problems fixed by Gnulib module stdio, together with module nonblocking:

• When writing to a non-blocking pipe whose buffer is full, this function fails with errno being set to ENOSPC instead of EAGAIN on some platforms: mingw, MSVC 9.

Portability problems fixed by Gnulib module stdio, together with module sigpipe:

• When writing to a pipe with no readers, this function fails, instead of obeying the current SIGPIPE handler, on some platforms: mingw, MSVC 9.

Portability problems not fixed by Gnulib:

• On Windows platforms (excluding Cygwin), this function does not set errno upon failure.
• On some platforms, this function does not set errno or the stream error indicator on attempts to write to a read-only stream: Cygwin 1.7.9.
• This function crashes if the stream's file descriptor has already been closed, if MSVC_INVALID_PARAMETER_HANDLING is HAIRY_LIBRARY_HANDLING or SANE_LIBRARY_HANDLING, on some platforms: MSVC 9.