X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Fpopen.m4;h=9a12b0eca2a3c3b88a41a4feb8f455b05b788623;hb=5191b3546cfb6c163228c23f214e325ddf60d46f;hp=f774a9efa4c87ba32f4da06a29b1b6821131ba98;hpb=a8f637e3c49275e6789c05d67c1fbd1751e5610a;p=gnulib.git

diff --git a/m4/popen.m4 b/m4/popen.m4
index f774a9efa..9a12b0eca 100644
--- a/m4/popen.m4
+++ b/m4/popen.m4
@@ -1,5 +1,5 @@
-# popen.m4 serial 1
-dnl Copyright (C) 2009 Free Software Foundation, Inc.
+# popen.m4 serial 5
+dnl Copyright (C) 2009-2013 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.
@@ -7,28 +7,40 @@ dnl with or without modifications, as long as this notice is preserved.
 AC_DEFUN([gl_FUNC_POPEN],
 [
   AC_REQUIRE([gl_STDIO_H_DEFAULTS])
-  AC_CACHE_CHECK([whether popen works with closed stdin],
-    [gl_cv_func_popen_works],
-    [
-      AC_RUN_IFELSE([AC_LANG_PROGRAM([[#include <stdio.h>
-]], [FILE *child;
-     fclose (stdin);
-     fclose (stdout);
-     child = popen ("echo a", "r");
-     return !(fgetc (child) == 'a' && pclose (child) == 0);
-])], [gl_cv_func_popen_works=yes], [gl_cv_func_popen_works=no],
-     dnl For now, only cygwin 1.5 or older is known to be broken.
-     [gl_cv_func_popen_works='guessing yes'])
-  ])
-  if test "$gl_cv_func_popen_works" = no; then
-    REPLACE_POPEN=1
-    AC_LIBOBJ([popen])
-    gl_PREREQ_POPEN
+  AC_CHECK_FUNCS_ONCE([popen])
+  if test $ac_cv_func_popen = no; then
+    HAVE_POPEN=0
+  else
+    AC_CACHE_CHECK([whether popen works with closed stdin],
+      [gl_cv_func_popen_works],
+      [
+        AC_RUN_IFELSE(
+          [AC_LANG_PROGRAM(
+             [[#include <stdio.h>]],
+             [[int result = 0;
+               FILE *child;
+               fclose (stdin);
+               fclose (stdout);
+               child = popen ("echo a", "r");
+               if (fgetc (child) != 'a')
+                 result |= 1;
+               if (pclose (child) != 0)
+                 result |= 2;
+               return result;
+             ]])],
+          [gl_cv_func_popen_works=yes],
+          [gl_cv_func_popen_works=no],
+          dnl For now, only cygwin 1.5 or older is known to be broken.
+          [gl_cv_func_popen_works='guessing yes'])
+      ])
+    if test "$gl_cv_func_popen_works" = no; then
+      REPLACE_POPEN=1
+    fi
   fi
 ])
 
 # Prerequisites of lib/popen.c.
 AC_DEFUN([gl_PREREQ_POPEN],
 [
-  AC_REQUIRE([AC_C_INLINE])
+  :
 ])