@node write
@section @code{write}
@findex write

POSIX specification:@* @url{https://pubs.opengroup.org/onlinepubs/9699919799/functions/write.html}

Gnulib module: write, nonblocking, sigpipe

Portability problems fixed by Gnulib module @code{write}:
@itemize
@item
This function is declared in a different header file (namely, @code{<io.h>})
on some platforms:
mingw, MSVC 14.
@item
This function crashes when invoked with invalid arguments on some platforms:
MSVC 14.
@end itemize

Portability problems fixed by Gnulib module @code{stdio}, together with module @code{nonblocking}:
@itemize
@item
When writing to a non-blocking pipe whose buffer is full, this function fails
with @code{errno} being set to @code{ENOSPC} instead of @code{EAGAIN} on some
platforms:
mingw, MSVC 14.
@item
When writing to a non-blocking pipe on which no reader is currently waiting
an amount of bytes that exceeds the pipe buffer's size, then---even if the
pipe's buffer is empty---this function fails, instead of performing a partial
write into the pipe buffer, on some platforms:
mingw, MSVC 14.
@end itemize

Portability problems fixed by Gnulib module @code{stdio}, together with module @code{sigpipe}:
@itemize
@item
When writing to a pipe with no readers, this function fails with error
@code{EINVAL}, instead of obeying the current @code{SIGPIPE} handler, on
some platforms:
mingw, MSVC 14.
@end itemize

Portability problems not fixed by Gnulib:
@itemize
@item
This function may fail with error @code{EINTR}, even in programs that don't
install any signal handlers, on some platforms:
macOS 11.1.
@end itemize

For handling @code{EINTR}, Gnulib provides a module @samp{safe-write} with a
function @code{safe_write}.