2 dnl Copyright (C) 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_POPEN],
9 AC_REQUIRE([gl_STDIO_H_DEFAULTS])
10 AC_CHECK_FUNCS_ONCE([popen])
11 if test $ac_cv_func_popen = no; then
14 AC_CACHE_CHECK([whether popen works with closed stdin],
15 [gl_cv_func_popen_works],
19 [[#include <stdio.h>]],
24 child = popen ("echo a", "r");
25 if (fgetc (child) != 'a')
27 if (pclose (child) != 0)
31 [gl_cv_func_popen_works=yes],
32 [gl_cv_func_popen_works=no],
33 dnl For now, only cygwin 1.5 or older is known to be broken.
34 [gl_cv_func_popen_works='guessing yes'])
36 if test "$gl_cv_func_popen_works" = no; then
42 # Prerequisites of lib/popen.c.
43 AC_DEFUN([gl_PREREQ_POPEN],