emacs/lib/dirfd.c

/* dirfd.c -- return the file descriptor associated with an open DIR*

   Copyright (C) 2001, 2006, 2008-2024 Free Software Foundation, Inc.

   This file is free software: you can redistribute it and/or modify
   it under the terms of the GNU Lesser General Public License as
   published by the Free Software Foundation; either version 2.1 of the
   License, or (at your option) any later version.

   This file is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public License
   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */

/* Written by Jim Meyering. */

#include <config.h>

#include <dirent.h>
#include <errno.h>

#if GNULIB_defined_DIR
# include "dirent-private.h"
#endif

int
dirfd (DIR *dir_p)
{
#if GNULIB_defined_DIR
  int fd = dir_p->fd_to_close;
  if (fd == -1)
    errno = EINVAL;
  return fd;
#else
  int fd = DIR_TO_FD (dir_p);
  if (fd == -1)
    errno = ENOTSUP;

  return fd;
#endif
}