X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Fdup2.m4;h=89638a0bfe3f2d82edfb2966adbe6065467c8314;hb=46f5f314f34a08c9305758482d7d2fdb0e999d09;hp=5c2cc9674c1f467672b3c25d9dafb0ee6ceb6514;hpb=1a9afb04e6f2fb36d17b3837942165cd1a0c50ac;p=gnulib.git

diff --git a/m4/dup2.m4 b/m4/dup2.m4
index 5c2cc9674..89638a0bf 100644
--- a/m4/dup2.m4
+++ b/m4/dup2.m4
@@ -1,5 +1,5 @@
-#serial 14
-dnl Copyright (C) 2002, 2005, 2007, 2009-2011 Free Software Foundation, Inc.
+#serial 20
+dnl Copyright (C) 2002, 2005, 2007, 2009-2014 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.
@@ -39,35 +39,49 @@ AC_DEFUN([gl_FUNC_DUP2],
             /* Many gnulib modules require POSIX conformance of EBADF.  */
             if (dup2 (2, 1000000) == -1 && errno != EBADF)
               result |= 16;
+            /* Flush out some cygwin core dumps.  */
+            if (dup2 (2, -1) != -1 || errno != EBADF)
+              result |= 32;
+            dup2 (2, 255);
+            dup2 (2, 256);
             return result;
            ])
         ],
         [gl_cv_func_dup2_works=yes], [gl_cv_func_dup2_works=no],
         [case "$host_os" in
            mingw*) # on this platform, dup2 always returns 0 for success
-             gl_cv_func_dup2_works=no;;
+             gl_cv_func_dup2_works="guessing no" ;;
            cygwin*) # on cygwin 1.5.x, dup2(1,1) returns 0
-             gl_cv_func_dup2_works=no;;
+             gl_cv_func_dup2_works="guessing no" ;;
            linux*) # On linux between 2008-07-27 and 2009-05-11, dup2 of a
                    # closed fd may yield -EBADF instead of -1 / errno=EBADF.
-             gl_cv_func_dup2_works=no;;
+             gl_cv_func_dup2_works="guessing no" ;;
            freebsd*) # on FreeBSD 6.1, dup2(1,1000000) gives EMFILE, not EBADF.
-             gl_cv_func_dup2_works=no;;
+             gl_cv_func_dup2_works="guessing no" ;;
            haiku*) # on Haiku alpha 2, dup2(1, 1) resets FD_CLOEXEC.
-             gl_cv_func_dup2_works=no;;
-           *) gl_cv_func_dup2_works=yes;;
+             gl_cv_func_dup2_works="guessing no" ;;
+           *) gl_cv_func_dup2_works="guessing yes" ;;
          esac])
       ])
-    if test "$gl_cv_func_dup2_works" = no; then
-      REPLACE_DUP2=1
-    fi
+    case "$gl_cv_func_dup2_works" in
+      *yes) ;;
+      *)
+        REPLACE_DUP2=1
+        AC_CHECK_FUNCS([setdtablesize])
+        ;;
+    esac
   fi
   dnl Replace dup2() for supporting the gnulib-defined fchdir() function,
   dnl to keep fchdir's bookkeeping up-to-date.
   m4_ifdef([gl_FUNC_FCHDIR], [
     gl_TEST_FCHDIR
     if test $HAVE_FCHDIR = 0; then
-      REPLACE_DUP2=1
+      if test $HAVE_DUP2 = 1; then
+        REPLACE_DUP2=1
+      fi
     fi
   ])
 ])
+
+# Prerequisites of lib/dup2.c.
+AC_DEFUN([gl_PREREQ_DUP2], [])