1/* Copyright (C) 1991-2022 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 <https://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. */
26char *
27ctermid (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}
36

source code of glibc/sysdeps/posix/ctermid.c