2 dnl Copyright (C) 2002, 2005, 2007, 2009-2011 Free Software Foundation, Inc.
3 dnl This file is free software; the Free Software Foundation
4 dnl gives unlimited permission to copy and/or distribute it,
5 dnl with or without modifications, as long as this notice is preserved.
7 AC_DEFUN([gl_FUNC_DUP2],
9 AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
10 AC_REQUIRE([AC_CANONICAL_HOST])
11 m4_ifdef([gl_FUNC_DUP2_OBSOLETE], [
12 AC_CHECK_FUNCS_ONCE([dup2])
13 if test $ac_cv_func_dup2 = no; then
18 AC_DEFINE([HAVE_DUP2], [1], [Define to 1 if you have the 'dup2' function.])
20 AC_CHECK_FUNCS_ONCE([fcntl])
21 if test $HAVE_DUP2 = 1; then
22 AC_CACHE_CHECK([whether dup2 works], [gl_cv_func_dup2_works],
24 AC_LANG_PROGRAM([[#include <unistd.h>
29 if (fcntl (1, F_SETFD, FD_CLOEXEC) == -1)
35 if (fcntl (1, F_GETFD) != FD_CLOEXEC)
39 if (dup2 (0, 0) != -1)
41 /* Many gnulib modules require POSIX conformance of EBADF. */
42 if (dup2 (2, 1000000) == -1 && errno != EBADF)
47 [gl_cv_func_dup2_works=yes], [gl_cv_func_dup2_works=no],
49 mingw*) # on this platform, dup2 always returns 0 for success
50 gl_cv_func_dup2_works=no;;
51 cygwin*) # on cygwin 1.5.x, dup2(1,1) returns 0
52 gl_cv_func_dup2_works=no;;
53 linux*) # On linux between 2008-07-27 and 2009-05-11, dup2 of a
54 # closed fd may yield -EBADF instead of -1 / errno=EBADF.
55 gl_cv_func_dup2_works=no;;
56 freebsd*) # on FreeBSD 6.1, dup2(1,1000000) gives EMFILE, not EBADF.
57 gl_cv_func_dup2_works=no;;
58 haiku*) # on Haiku alpha 2, dup2(1, 1) resets FD_CLOEXEC.
59 gl_cv_func_dup2_works=no;;
60 *) gl_cv_func_dup2_works=yes;;
63 if test "$gl_cv_func_dup2_works" = no; then
69 AC_DEFUN([gl_REPLACE_DUP2],
71 AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
72 AC_CHECK_FUNCS_ONCE([dup2])
73 if test $ac_cv_func_dup2 = yes; then