-# poll.m4 serial 3
-dnl Copyright (c) 2003 Free Software Foundation, Inc.
+# poll.m4 serial 6
+dnl Copyright (c) 2003, 2005, 2006 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
[
AC_CHECK_HEADERS(poll.h)
if test "$ac_cv_header_poll_h" = no; then
- POLL_H=poll.h
+ gl_cv_func_poll=no
else
- POLL_H=
+ AC_CHECK_FUNC(poll,
+ [# Check whether poll() works on special files (like /dev/null) and
+ # and ttys (like /dev/tty). On MacOS X 10.4.0 and AIX 5.3, it doesn't.
+ AC_TRY_RUN([
+#include <fcntl.h>
+#include <poll.h>
+ int main()
+ {
+ struct pollfd ufd;
+ /* Try /dev/null for reading. */
+ ufd.fd = open ("/dev/null", O_RDONLY);
+ if (ufd.fd < 0)
+ /* If /dev/null does not exist, it's not MacOS X nor AIX. */
+ return 0;
+ ufd.events = POLLIN;
+ ufd.revents = 0;
+ if (!(poll (&ufd, 1, 0) == 1 && ufd.revents == POLLIN))
+ return 1;
+ /* Try /dev/null for writing. */
+ ufd.fd = open ("/dev/null", O_WRONLY);
+ if (ufd.fd < 0)
+ /* If /dev/null does not exist, it's not MacOS X nor AIX. */
+ return 0;
+ ufd.events = POLLOUT;
+ ufd.revents = 0;
+ if (!(poll (&ufd, 1, 0) == 1 && ufd.revents == POLLOUT))
+ return 1;
+ /* Trying /dev/tty may be too environment dependent. */
+ return 0;
+ }],
+ [gl_cv_func_poll=yes],
+ [gl_cv_func_poll=no],
+ [# When cross-compiling, assume that poll() works everywhere except on
+ # MacOS X or AIX, regardless of its version.
+ AC_EGREP_CPP([MacOSX], [
+#if (defined(__APPLE__) && defined(__MACH__)) || defined(_AIX)
+This is MacOSX or AIX
+#endif
+], [gl_cv_func_poll=no], [gl_cv_func_poll=yes])])])
fi
- AC_SUBST([POLL_H])
-
- AC_REPLACE_FUNCS(poll)
- if test $ac_cv_func_poll = no; then
+ if test $gl_cv_func_poll = yes; then
+ AC_DEFINE([HAVE_POLL], 1,
+ [Define to 1 if you have the 'poll' function and it works.])
+ POLL_H=
+ else
+ AC_LIBOBJ(poll)
+ AC_DEFINE(poll, rpl_poll,
+ [Define to poll if the replacement function should be used.])
gl_PREREQ_POLL
+ POLL_H=poll.h
fi
+ AC_SUBST([POLL_H])
])
# Prerequisites of lib/poll.c.