io/dup2.c

   1 /* Copyright (C) 1991, 1995, 1996, 1997, 2002 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #include <errno.h>
  20 #include <fcntl.h>
  21 #include <unistd.h>
  22
  23
  24 /* Duplicate FD to FD2, closing the old FD2 and making FD2 be
  25    open the same file as FD is.  Return FD2 or -1.  */
  26 int
  27 __dup2 (fd, fd2)
  28      int fd;
  29      int fd2;
  30 {
  31   if (fd < 0 || fd2 < 0)
  32     {
  33       __set_errno (EBADF);
  34       return -1;
  35     }
  36
  37   if (fd == fd2)
  38     /* No way to check that they are valid.  */
  39     return fd2;
  40
  41   __set_errno (ENOSYS);
  42   return -1;
  43 }
  44 libc_hidden_def (__dup2)
  45 stub_warning (dup2)
  46
  47 weak_alias (__dup2, dup2)
  48 #include <stub-tag.h>