-# dup2.m4 serial 2
-dnl Copyright (C) 2002 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.
AC_DEFUN([gl_FUNC_DUP2],
[
- AC_REPLACE_FUNCS(dup2)
- if test $ac_cv_func_dup2 = no; then
- gl_PREREQ_DUP2
+ AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+ AC_REQUIRE([AC_CANONICAL_HOST])
+ m4_ifdef([gl_FUNC_DUP2_OBSOLETE], [
+ AC_CHECK_FUNCS_ONCE([dup2])
+ if test $ac_cv_func_dup2 = no; then
+ HAVE_DUP2=0
+ AC_LIBOBJ([dup2])
+ fi
+ ], [
+ AC_DEFINE([HAVE_DUP2], [1], [Define to 1 if you have the 'dup2' function.])
+ ])
+ AC_CHECK_FUNCS_ONCE([fcntl])
+ if test $HAVE_DUP2 = 1; then
+ AC_CACHE_CHECK([whether dup2 works], [gl_cv_func_dup2_works],
+ [AC_RUN_IFELSE([
+ AC_LANG_PROGRAM([[#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>]],
+ [int result = 0;
+#if HAVE_FCNTL
+ if (fcntl (1, F_SETFD, FD_CLOEXEC) == -1)
+ result |= 1;
+#endif HAVE_FCNTL
+ if (dup2 (1, 1) == 0)
+ result |= 2;
+#if HAVE_FCNTL
+ if (fcntl (1, F_GETFD) != FD_CLOEXEC)
+ result |= 4;
+#endif
+ close (0);
+ if (dup2 (0, 0) != -1)
+ result |= 8;
+ /* Many gnulib modules require POSIX conformance of EBADF. */
+ if (dup2 (2, 1000000) == -1 && errno != EBADF)
+ result |= 16;
+ return result;
+ ])
+ ],
+ [gl_cv_func_dup2_works=yes], [gl_cv_func_dup2_works=no],
+ [case "$host_os" in
+ mingw*) # on this platform, dup2 always returns 0 for success
+ gl_cv_func_dup2_works=no;;
+ 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;;
+ haiku*) # on Haiku alpha 2, dup2(1, 1) resets FD_CLOEXEC.
+ 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
])
-# Prerequisites of lib/dup2.c.
-AC_DEFUN([gl_PREREQ_DUP2], [
- AC_CHECK_HEADERS_ONCE(fcntl.h unistd.h)
+AC_DEFUN([gl_REPLACE_DUP2],
+[
+ AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+ AC_CHECK_FUNCS_ONCE([dup2])
+ if test $ac_cv_func_dup2 = yes; then
+ REPLACE_DUP2=1
+ fi
+ AC_LIBOBJ([dup2])
])