1  /* dirfd.c -- return the file descriptor associated with an open DIR*
       2  
       3     Copyright (C) 2001, 2006, 2008-2023 Free Software Foundation, Inc.
       4  
       5     This file is free software: you can redistribute it and/or modify
       6     it under the terms of the GNU Lesser General Public License as
       7     published by the Free Software Foundation; either version 2.1 of the
       8     License, or (at your option) any later version.
       9  
      10     This file is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      13     GNU Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public License
      16     along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
      17  
      18  /* Written by Jim Meyering. */
      19  
      20  #include <config.h>
      21  
      22  #include <dirent.h>
      23  #include <errno.h>
      24  
      25  #if GNULIB_defined_DIR
      26  # include "dirent-private.h"
      27  #endif
      28  
      29  int
      30  dirfd (DIR *dir_p)
      31  {
      32  #if GNULIB_defined_DIR
      33    int fd = dir_p->fd_to_close;
      34    if (fd == -1)
      35      errno = EINVAL;
      36    return fd;
      37  #else
      38    int fd = DIR_TO_FD (dir_p);
      39    if (fd == -1)
      40      errno = ENOTSUP;
      41  
      42    return fd;
      43  #endif
      44  }