# fdopen.m4 serial 4

dnl Copyright (C) 2011-2020 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_FDOPEN],

[

  AC_REQUIRE([gl_STDIO_H_DEFAULTS])

  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles

  m4_ifdef([gl_MSVC_INVAL], [

    AC_REQUIRE([gl_MSVC_INVAL])

    if test $HAVE_MSVC_INVALID_PARAMETER_HANDLER = 1; then

      REPLACE_FDOPEN=1

    fi

  ])

  if test $REPLACE_FDOPEN = 0; then

    dnl Test whether fdopen() sets errno when it fails due to a bad fd argument.

    AC_CACHE_CHECK([whether fdopen sets errno], [gl_cv_func_fdopen_works],

      [

        AC_RUN_IFELSE(

          [AC_LANG_SOURCE([[

#include <stdio.h>

#include <errno.h>

int

main (void)

{

  FILE *fp;

  errno = 0;

  fp = fdopen (-1, "r");

  if (fp == NULL && errno == 0)

    return 1;

  return 0;

}]])],

          [gl_cv_func_fdopen_works=yes],

          [gl_cv_func_fdopen_works=no],

          [case "$host_os" in

             mingw*) gl_cv_func_fdopen_works="guessing no" ;;

             *)      gl_cv_func_fdopen_works="guessing yes" ;;

           esac

          ])

      ])

    case "$gl_cv_func_fdopen_works" in

      *no) REPLACE_FDOPEN=1 ;;

    esac

  fi

])

dnl Prerequisites of lib/fdopen.c.

AC_DEFUN([gl_PREREQ_FDOPEN], [])