2 dnl Copyright (C) 2009 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_CACHE_CHECK([whether popen works with closed stdin],
11 [gl_cv_func_popen_works],
13 AC_RUN_IFELSE([AC_LANG_PROGRAM([[#include <stdio.h>
17 child = popen ("echo a", "r");
18 return !(fgetc (child) == 'a' && pclose (child) == 0);
19 ])], [gl_cv_func_popen_works=yes], [gl_cv_func_popen_works=no],
20 dnl For now, only cygwin 1.5 or older is known to be broken.
21 [gl_cv_func_popen_works='guessing yes'])
23 if test "$gl_cv_func_popen_works" = no; then
30 # Prerequisites of lib/popen.c.
31 AC_DEFUN([gl_PREREQ_POPEN],