Import upstream version 1.26

[debian/tar] / m4 / dup2.m4

diff --git a/m4/dup2.m4 b/m4/dup2.m4
index 998d66f83b1f3812227ac15199331d42d83b96ed..def263b87a85b7ccd38e0c539f894718817a75c9 100644 (file)
--- a/m4/dup2.m4
+++ b/m4/dup2.m4
@@ -1,5 +1,5 @@
-#serial 10
-dnl Copyright (C) 2002, 2005, 2007, 2009-2010 Free Software Foundation, Inc.
+#serial 12
+dnl Copyright (C) 2002, 2005, 2007, 2009-2011 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.
@@ -8,7 +8,7 @@ AC_DEFUN([gl_FUNC_DUP2],
 [
   AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
   AC_REQUIRE([AC_CANONICAL_HOST])
-  AC_CHECK_FUNCS_ONCE([dup2])
+  AC_CHECK_FUNCS_ONCE([dup2 fcntl])
   if test $ac_cv_func_dup2 = no; then
     HAVE_DUP2=0
     AC_LIBOBJ([dup2])
@@ -16,16 +16,26 @@ AC_DEFUN([gl_FUNC_DUP2],
     AC_CACHE_CHECK([whether dup2 works], [gl_cv_func_dup2_works],
       [AC_RUN_IFELSE([
          AC_LANG_PROGRAM([[#include <unistd.h>
+#include <fcntl.h>
 #include <errno.h>]],
-           [if (dup2 (1, 1) == 0)
-              return 1;
+           [int result = 0;
+#if HAVE_FCNTL
+            if (fcntl (1, F_SETFD, FD_CLOEXEC) == -1)
+              result |= 1;
+#endif HAVE_FCNTL
+            if (dup2 (1, 1) == 0)
+              result |= 2;
+#if HAVE_FCNTL
+            if (fcntl (1, F_GETFD) != FD_CLOEXEC)
+              result |= 4;
+#endif
             close (0);
             if (dup2 (0, 0) != -1)
-              return 2;
+              result |= 8;
             /* Many gnulib modules require POSIX conformance of EBADF.  */
-            if (dup2 (1, 1000000) == -1 && errno != EBADF)
-              return 3;
-            return 0;
+            if (dup2 (2, 1000000) == -1 && errno != EBADF)
+              result |= 16;
+            return result;
            ])
         ],
         [gl_cv_func_dup2_works=yes], [gl_cv_func_dup2_works=no],
@@ -39,6 +49,8 @@ AC_DEFUN([gl_FUNC_DUP2],
              gl_cv_func_dup2_works=no;;
            freebsd*) # on FreeBSD 6.1, dup2(1,1000000) gives EMFILE, not EBADF.
              gl_cv_func_dup2_works=no;;
+           haiku*) # on Haiku alpha 2, dup2(1, 1) resets FD_CLOEXEC.
+             gl_cv_func_dup2_works=no;;
            *) gl_cv_func_dup2_works=yes;;
          esac])
       ])