2 dnl Copyright (C) 2002, 2005, 2007, 2009-2010 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 AC_CHECK_FUNCS_ONCE([dup2])
12 if test $ac_cv_func_dup2 = no; then
16 AC_CACHE_CHECK([whether dup2 works], [gl_cv_func_dup2_works],
18 AC_LANG_PROGRAM([[#include <unistd.h>
20 [if (dup2 (1, 1) == 0)
23 if (dup2 (0, 0) != -1)
25 /* Many gnulib modules require POSIX conformance of EBADF. */
26 if (dup2 (1, 1000000) == -1 && errno != EBADF)
31 [gl_cv_func_dup2_works=yes], [gl_cv_func_dup2_works=no],
33 mingw*) # on this platform, dup2 always returns 0 for success
34 gl_cv_func_dup2_works=no;;
35 cygwin*) # on cygwin 1.5.x, dup2(1,1) returns 0
36 gl_cv_func_dup2_works=no;;
37 linux*) # On linux between 2008-07-27 and 2009-05-11, dup2 of a
38 # closed fd may yield -EBADF instead of -1 / errno=EBADF.
39 gl_cv_func_dup2_works=no;;
40 freebsd*) # on FreeBSD 6.1, dup2(1,1000000) gives EMFILE, not EBADF.
41 gl_cv_func_dup2_works=no;;
42 *) gl_cv_func_dup2_works=yes;;
45 if test "$gl_cv_func_dup2_works" = no; then
51 AC_DEFUN([gl_REPLACE_DUP2],
53 AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
54 if test $ac_cv_func_dup2 = yes; then