poll
====

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

Gnulib module: poll

Portability problems fixed by Gnulib:

  * This function is missing on some platforms: mingw, MSVC 9, BeOS, HP NonStop.

  * This function doesn't work on special files like /dev/null and ttys like /dev/tty on some platforms: Mac OS X 10.4.0, AIX 5.3.

Portability problems not fixed by Gnulib:

  * Under BeOS, Gnulib's poll replacement can only be called on descriptors created by the socket function, not on regular file descriptors.

  * Under Windows, when passing a pipe, Gnulib's poll replacement might return 0 even before the timeout has passed.  Programs using it with pipes can thus busy wait.

  * Under HP NonStop, file descriptors other than sockets do not support POLLHUP; they will return a "readable" status instead.