# popen.m4 serial 2
dnl Copyright (C) 2009, 2010 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_POPEN],
[
  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
  AC_CACHE_CHECK([whether popen works with closed stdin],
    [gl_cv_func_popen_works],
    [
      AC_RUN_IFELSE([AC_LANG_PROGRAM([[#include <stdio.h>
]], [FILE *child;
     fclose (stdin);
     fclose (stdout);
     child = popen ("echo a", "r");
     return !(fgetc (child) == 'a' && pclose (child) == 0);
])], [gl_cv_func_popen_works=yes], [gl_cv_func_popen_works=no],
     dnl For now, only cygwin 1.5 or older is known to be broken.
     [gl_cv_func_popen_works='guessing yes'])
  ])
  if test "$gl_cv_func_popen_works" = no; then
    REPLACE_POPEN=1
    AC_LIBOBJ([popen])
    gl_PREREQ_POPEN
  fi
])

# Prerequisites of lib/popen.c.
AC_DEFUN([gl_PREREQ_POPEN],
[
  :
])