libiberty/filedescriptor.c

   1 /* File descriptor related functions.
   2
   3    Copyright (C) 2019-2022 Free Software Foundation, Inc.
   4
   5    This file is part of the libiberty library.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 51 Franklin Street - Fifth Floor,
  20    Boston, MA 02110-1301, USA.  */
  21
  22 #include "config.h"
  23 #include "ansidecl.h"
  24 #include "libiberty.h"
  25
  26 #ifdef HAVE_FCNTL_H
  27 #include <fcntl.h>
  28 #endif
  29
  30 #if defined (_WIN32)
  31 #define WIN32_LEAN_AND_MEAN
  32 #include <windows.h> /* for GetFullPathName */
  33 #endif
  34 /* Return true when FD file descriptor exists.  */
  35
  36 int
  37 is_valid_fd (int fd)
  38 {
  39 #if defined(_WIN32)
  40   HANDLE h = (HANDLE) _get_osfhandle (fd);
  41   return h != (HANDLE) -1;
  42 #elif defined(F_GETFD)
  43   return fcntl (fd, F_GETFD) >= 0;
  44 #else
  45   return dup2 (fd, fd) < 0;
  46 #endif
  47 }