/* Invoke dup, but avoid some glitches.   Copyright (C) 2001 Free Software Foundation, Inc.   This program is free software; you can redistribute it and/or modify   it under the terms of the GNU General Public License as published by   the Free Software Foundation; either version 2, or (at your option)   any later version.   This program 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 General Public License for more details.   You should have received a copy of the GNU General Public License   along with this program; if not, write to the Free Software Foundation,   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  *//* Written by Paul Eggert.  */#if HAVE_CONFIG_H# include <config.h>#endif#include <errno.h>#ifndef errnoextern int errno;#endif#if HAVE_FCNTL_H# include <fcntl.h>#endif#if HAVE_UNISTD_H# include <unistd.h>#endif#ifndef STDERR_FILENO# define STDERR_FILENO 2#endif#include <unistd-safer.h>/* Like dup, but do not return STDIN_FILENO, STDOUT_FILENO, or   STDERR_FILENO.  */intdup_safer (int fd){#ifdef F_DUPFD  return fcntl (fd, F_DUPFD, STDERR_FILENO + 1);#else  int f = dup (fd);  if (0 <= f && f <= STDERR_FILENO)    {      int f1 = dup_safer (f);      int e = errno;      close (f);      errno = e;      f = f1;    }  return f;#endif}