chown: Update doc regarding AIX.

[gnulib.git] / m4 / poll.m4

diff --git a/m4/poll.m4 b/m4/poll.m4
index a23f504..3a7c186 100644 (file)
--- a/m4/poll.m4
+++ b/m4/poll.m4
@@ -1,27 +1,72 @@
-# poll.m4 serial 1
-dnl Copyright (c) 2003 Free Software Foundation, Inc.
-dnl This file is free software, distributed under the terms of the GNU
-dnl General Public License.  As a special exception to the GNU General
-dnl Public License, this file may be distributed as part of a program
-dnl that contains a configuration script generated by Autoconf, under
-dnl the same distribution terms as the rest of the program.
+# poll.m4 serial 9
+dnl Copyright (c) 2003, 2005, 2006, 2007, 2009, 2010 Free Software Foundation,
+dnl 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_DEFUN([gl_FUNC_POLL],
 [
-  AC_CHECK_HEADERS(poll.h)
-  if test x$ac_cv_header_poll_h = xno; then
-    AC_CONFIG_LINKS([lib/poll.h:lib/poll_.h])
+  AC_CHECK_HEADERS([poll.h])
+  if test "$ac_cv_header_poll_h" = no; then
+    gl_cv_func_poll=no
+  else
+    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_RUN_IFELSE([AC_LANG_SOURCE([[
+#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_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.
 AC_DEFUN([gl_PREREQ_POLL],
 [
-  AC_REQUIRE([AC_HEADER_TIME])
-  AC_CHECK_HEADERS_ONCE(sys/time.h)
+  AC_CHECK_HEADERS_ONCE([sys/ioctl.h sys/filio.h])
 ])