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glibc  2.9
unlockpt.c
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00001 /* Copyright (C) 1998 Free Software Foundation, Inc.
00002    This file is part of the GNU C Library.
00003    Contributed by Zack Weinberg <zack@rabi.phys.columbia.edu>, 1998.
00004 
00005    The GNU C Library is free software; you can redistribute it and/or
00006    modify it under the terms of the GNU Lesser General Public
00007    License as published by the Free Software Foundation; either
00008    version 2.1 of the License, or (at your option) any later version.
00009 
00010    The GNU C Library is distributed in the hope that it will be useful,
00011    but WITHOUT ANY WARRANTY; without even the implied warranty of
00012    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00013    Lesser General Public License for more details.
00014 
00015    You should have received a copy of the GNU Lesser General Public
00016    License along with the GNU C Library; if not, write to the Free
00017    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00018    02111-1307 USA.  */
00019 
00020 #include <errno.h>
00021 #include <stdlib.h>
00022 #include <sys/ioctl.h>
00023 #include <termios.h>
00024 
00025 
00026 /* Unlock the slave pseudo terminal associated with the master pseudo
00027    terminal specified by FD.  */
00028 int
00029 unlockpt (int fd)
00030 {
00031 #ifdef TIOCSPTLCK
00032   int save_errno = errno;
00033   int unlock = 0;
00034 
00035   if (__ioctl (fd, TIOCSPTLCK, &unlock))
00036     {
00037       if (errno == EINVAL)
00038        {
00039          __set_errno (save_errno);
00040          return 0;
00041        }
00042       else
00043        return -1;
00044     }
00045 #endif
00046   /* If we have no TIOCSPTLCK ioctl, all slave pseudo terminals are
00047      unlocked by default.  */
00048   return 0;
00049 }