dnl CF_FUNC_POLL version: 7 updated: 2012/06/09 16:22:17
dnl ------------
dnl See if the poll function really works.  Some platforms have poll(), but
dnl it does not work for terminals or files.
AC_DEFUN([CF_FUNC_POLL],[
AC_CACHE_CHECK(if poll really works,cf_cv_working_poll,[
AC_TRY_RUN([
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#ifdef HAVE_POLL_H
#include <poll.h>
#else
#include <sys/poll.h>
#endif
int main() {
	struct pollfd myfds;
	int ret;

	/* check for Darwin bug with respect to "devices" */
	myfds.fd = open("/dev/null", 1);	/* O_WRONLY */
	if (myfds.fd < 0)
		myfds.fd = 0;
	myfds.events = POLLIN;
	myfds.revents = 0;

	ret = poll(&myfds, 1, 100);

	if (ret < 0 || (myfds.revents & POLLNVAL)) {
		ret = -1;
	} else {
		int fd = 0;
		if (!isatty(fd)) {
			fd = open("/dev/tty", 2);	/* O_RDWR */
		}

		if (fd >= 0) {
			/* also check with standard input */
			myfds.fd = fd;
			myfds.events = POLLIN;
			myfds.revents = 0;
			ret = poll(&myfds, 1, 100);
		} else {
			ret = -1;
		}
	}
	${cf_cv_main_return:-return}(ret < 0);
}],
	[cf_cv_working_poll=yes],
	[cf_cv_working_poll=no],
	[cf_cv_working_poll=unknown])])
test "$cf_cv_working_poll" = "yes" && AC_DEFINE(HAVE_WORKING_POLL)
])dnl
