text: /* Copyright (C) 1998 Free Software Foundation, Inc.
     This file is part of the GNU C Library.
  
     The GNU C Library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Lesser General Public
     License as published by the Free Software Foundation; either
     version 2.1 of the License, or (at your option) any later version.
  
     The GNU C Library 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
     Lesser General Public License for more details.
  
     You should have received a copy of the GNU Lesser General Public
     License along with the GNU C Library; if not, write to the Free
     Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
     02111-1307 USA.  */
  
  #include <errno.h>
  #include <paths.h>
  #include <stdlib.h>
  #include <string.h>
  #include <sys/stat.h>
  #include <unistd.h>
  
  /* Static buffer for `ptsname'.  */
  static char buffer[sizeof (_PATH_TTY) + 2];
  
  
  /* Return the pathname of the pseudo terminal slave assoicated with
     the master FD is open on, or NULL on errors.
     The returned storage is good until the next call to this function.  */
  char *
  ptsname (int fd)
  {
    return __ptsname_r (fd, buffer, sizeof (buffer)) != 0 ? NULL : buffer;
  }
  
  
  /* Store at most BUFLEN characters of the pathname of the slave pseudo
     terminal associated with the master FD is open on in BUF.
     Return 0 on success, otherwise an error number.  */
  int
  __ptsname_r (int fd, char *buf, size_t buflen)
  {
    int save_errno = errno;
    struct stat st;
  
    if (buf == NULL)
      {
        __set_errno (EINVAL);
        return EINVAL;
      }
  
    if (!__isatty (fd))
      {
        __set_errno (ENOTTY);
        return ENOTTY;
      }
  
    if (buflen < strlen (_PATH_TTY) + 3)
      {
        __set_errno (ERANGE);
        return ERANGE;
      }
    
    if (__ttyname_r (fd, buf, buflen) != 0)
      return errno;
  
    buf[sizeof (_PATH_DEV) - 1] = 't';
    
    if (__stat (buf, &st) < 0)
      return errno;
  
    __set_errno (save_errno);
    return 0;
  }
  weak_alias (__ptsname_r, ptsname_r)
  