@node poll
@section @code{poll}
@findex poll

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

Gnulib module: poll

Portability problems fixed by Gnulib:
@itemize
@item
This function is missing on some platforms:
mingw, MSVC 14, HP NonStop.
@item
This function doesn't work on special files like @file{/dev/null} and ttys like
@file{/dev/tty} on some platforms:
macOS 10.15, AIX 5.3.
@end itemize

Portability problems not fixed by Gnulib:
@itemize
@item
Under Windows, when passing a pipe, Gnulib's @code{poll} replacement might
return 0 even before the timeout has passed.  Programs using it with pipes can
thus busy wait.
@item
On some platforms, file descriptors other than sockets do not support
POLLHUP; they will return a "readable" or "writable" status instead:
AIX 7.2, HP NonStop.
@end itemize
