Rearrange code.

diff --git a/m4/ChangeLog b/m4/ChangeLog
index 85495a40993e4360fbca1200accca5eda2498aab..538e9799be141f55a05b7d32f993ca702ad09fbc 100644 (file)
--- a/m4/ChangeLog
+++ b/m4/ChangeLog
@@ -1,3 +1,8 @@
+2006-04-23  Bruno Haible  <bruno@clisp.org>
+
+       * poll.m4 (gl_FUNC_POLL): Rearrange code, so that POLL_H gets
+       assigned exactly once.
+
 2006-04-23  Bruno Haible  <bruno@clisp.org>
 
        * poll.m4 (gl_FUNC_POLL): When cross-compiling, reject also the poll()

diff --git a/m4/poll.m4 b/m4/poll.m4
index 512c1d1045aff0b4ba6f11a09a4aaecd3c872f03..a3d0ab9d9a3894b0cc0b84398c2ced39f034fc04 100644 (file)
--- a/m4/poll.m4
+++ b/m4/poll.m4
@@ -8,63 +8,60 @@ AC_DEFUN([gl_FUNC_POLL],
 [
   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=
-  fi
-  AC_SUBST([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([
+    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. */
+         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;
-         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], [
+         }],
+         [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
   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.])
-  fi
-
-  if test $gl_cv_func_poll = no; then
-    POLL_H=poll.h # Avoid differing declaration from a system header.
+    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.