sysdeps/posix/ctermid.c

   1 /* Copyright (C) 1991 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 Library General Public License as
   6 published by the Free Software Foundation; either version 2 of the
   7 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 Library General Public License for more details.
  13
  14 You should have received a copy of the GNU Library General Public
  15 License along with the GNU C Library; see the file COPYING.LIB.  If
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 #include <ansidecl.h>
  20 #include <stdio.h>
  21 #include <string.h>
  22
  23
  24 /* Return the name of the controlling terminal.
  25    If S is not NULL, the name is copied into it (it should be at
  26    least L_ctermid bytes long), otherwise a static buffer is used.  */
  27 char *
  28 DEFUN(ctermid, (s), char *s)
  29 {
  30   static char name[L_ctermid];
  31
  32   if (name[0] == '\0')
  33     (void) strcpy(name, "/dev/tty");
  34
  35   if (s == NULL)
  36     return(name);
  37
  38   return(strcpy(s, name));
  39 }