# freopen.m4 serial 6

dnl Copyright (C) 2007-2017 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_FREOPEN],

[

  AC_REQUIRE([gl_STDIO_H_DEFAULTS])

  AC_REQUIRE([AC_CANONICAL_HOST])

  case "$host_os" in

    mingw* | pw* | os2*)

      REPLACE_FREOPEN=1

      ;;

    *)

      AC_CACHE_CHECK([whether freopen works on closed fds],

        [gl_cv_func_freopen_works_on_closed],

        [AC_RUN_IFELSE(

           [AC_LANG_PROGRAM(

              [[#include <stdio.h>

                #include <unistd.h>

              ]],

              [[close (0);

                return !(freopen ("/dev/null", "r", stdin)

                         && getchar () == EOF

                         && !ferror (stdin) && feof (stdin));]])],

           [gl_cv_func_freopen_works_on_closed=yes],

           [gl_cv_func_freopen_works_on_closed=no],

           [case $host_os in

              *gnu*) gl_cv_func_freopen_works_on_closed="guessing no" ;;

              *)     gl_cv_func_freopen_works_on_closed="guessing yes";;

            esac])])

      case $gl_cv_func_freopen_works_on_closed in

        *no) REPLACE_FREOPEN=1;;

      esac

  esac

])

# Prerequisites of lib/freopen.c.

AC_DEFUN([gl_PREREQ_FREOPEN], [:])