ctermid(3) Library Functions Manual ctermid(3)

ctermid - get controlling terminal name

Standard C library (libc, -lc)

#include <stdio.h>
char *ctermid(char *s);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):



ctermid() returns a string which is the pathname for the current controlling terminal for this process. If s is NULL, a static buffer is used, otherwise s points to a buffer used to hold the terminal pathname. The symbolic constant L_ctermid is the maximum number of characters in the returned pathname.

The pointer to the pathname.

For an explanation of the terms used in this section, see attributes(7).

Interface Attribute Value
ctermid () Thread safety MT-Safe


POSIX.1-2001, Svr4.

The returned pathname may not uniquely identify the controlling terminal; it may, for example, be /dev/tty.

It is not assured that the program can open the terminal.


2024-05-02 Linux man-pages 6.8