X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Fdup2.m4;h=998d66f83b1f3812227ac15199331d42d83b96ed;hb=89b39efd31cd0ffdaf05c9785c1af1e479728472;hp=816a73406807765226c9da22ab36a4678cd43e7c;hpb=4475e25b6a19e31e5783781f2132cdbd05bcf7c4;p=gnulib.git

diff --git a/m4/dup2.m4 b/m4/dup2.m4
index 816a73406..998d66f83 100644
--- a/m4/dup2.m4
+++ b/m4/dup2.m4
@@ -1,5 +1,5 @@
-#serial 8
-dnl Copyright (C) 2002, 2005, 2007, 2009 Free Software Foundation, Inc.
+#serial 10
+dnl Copyright (C) 2002, 2005, 2007, 2009-2010 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.
@@ -15,38 +15,44 @@ AC_DEFUN([gl_FUNC_DUP2],
   else
     AC_CACHE_CHECK([whether dup2 works], [gl_cv_func_dup2_works],
       [AC_RUN_IFELSE([
-         AC_LANG_PROGRAM([[#include <unistd.h>]],
+         AC_LANG_PROGRAM([[#include <unistd.h>
+#include <errno.h>]],
            [if (dup2 (1, 1) == 0)
               return 1;
             close (0);
             if (dup2 (0, 0) != -1)
-              return 1;
+              return 2;
+            /* Many gnulib modules require POSIX conformance of EBADF.  */
+            if (dup2 (1, 1000000) == -1 && errno != EBADF)
+              return 3;
             return 0;
            ])
         ],
-	[gl_cv_func_dup2_works=yes], [gl_cv_func_dup2_works=no],
-	[case "$host_os" in
-	   mingw*) # on this platform, dup2 always returns 0 for success
-	     gl_cv_func_dup2_works=no;;
-	   cygwin*) # on cygwin 1.5.x, dup2(1,1) returns 0
-	     gl_cv_func_dup2_works=no;;
-	   linux*) # On linux between 2008-07-27 and 2009-05-11, dup2 of a
-	           # closed fd may yield -EBADF instead of -1 / errno=EBADF.
-	     gl_cv_func_dup2_works=no;;
-	   *) gl_cv_func_dup2_works=yes;;
-	 esac])
+        [gl_cv_func_dup2_works=yes], [gl_cv_func_dup2_works=no],
+        [case "$host_os" in
+           mingw*) # on this platform, dup2 always returns 0 for success
+             gl_cv_func_dup2_works=no;;
+           cygwin*) # on cygwin 1.5.x, dup2(1,1) returns 0
+             gl_cv_func_dup2_works=no;;
+           linux*) # On linux between 2008-07-27 and 2009-05-11, dup2 of a
+                   # closed fd may yield -EBADF instead of -1 / errno=EBADF.
+             gl_cv_func_dup2_works=no;;
+           freebsd*) # on FreeBSD 6.1, dup2(1,1000000) gives EMFILE, not EBADF.
+             gl_cv_func_dup2_works=no;;
+           *) gl_cv_func_dup2_works=yes;;
+         esac])
       ])
     if test "$gl_cv_func_dup2_works" = no; then
       gl_REPLACE_DUP2
     fi
   fi
-  AC_DEFINE_UNQUOTED([REPLACE_DUP2], [$REPLACE_DUP2],
-    [Define to 1 if dup2 returns 0 instead of the target fd.])
 ])
 
 AC_DEFUN([gl_REPLACE_DUP2],
 [
   AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
-  REPLACE_DUP2=1
+  if test $ac_cv_func_dup2 = yes; then
+    REPLACE_DUP2=1
+  fi
   AC_LIBOBJ([dup2])
 ])