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#serial 6
dnl Copyright (C) 2002, 2005, 2007, 2009 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_REQUIRE([gl_UNISTD_H_DEFAULTS])
AC_REQUIRE([AC_CANONICAL_HOST])
AC_CHECK_FUNCS_ONCE([dup2])
if test $ac_cv_func_dup2 = no; then
HAVE_DUP2=0
AC_LIBOBJ([dup2])
else
AC_CACHE_CHECK([whether dup2 works], [gl_cv_func_dup2_works],
[AC_RUN_IFELSE([AC_LANG_PROGRAM([[
#include <unistd.h>
]], [return 1 - dup2 (1, 1);])],
[gl_cv_func_dup2_works=yes], [gl_cv_func_dup2_works=no],
[case "$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;;
*) gl_cv_func_dup2_works=yes;;
esac])])
if test "$gl_cv_func_dup2_works" = no; then
REPLACE_DUP2=1
AC_LIBOBJ([dup2])
fi
fi
AC_DEFINE_UNQUOTED([REPLACE_DUP2], [$REPLACE_DUP2],
[Define to 1 if dup2 returns 0 instead of the target fd.])
])
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