sysdeps/posix/ctermid.c

   1 /* Copyright (C) 1991-2015 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, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <stdio.h>
  19 #include <string.h>
  20
  21
  22 /* Return the name of the controlling terminal.  If S is not NULL, the
  23    name is copied into it (it should be at least L_ctermid bytes
  24    long), otherwise we return a pointer to a non-const but read-only
  25    string literal, that POSIX states the caller must not modify.  */
  26 char *
  27 ctermid (char *s)
  28 {
  29   char *name = (char /*drop const*/ *) "/dev/tty";
  30
  31   if (s == NULL)
  32     return name;
  33
  34   return strcpy (s, name);
  35 }