NAME

ctermid — generate terminal pathname

LIBRARY

Standard C Library (libc, -lc)

SYNOPSIS

#include <stdio.h>

char *
ctermid(char *buf);

char *
ctermid_r(char *buf);

DESCRIPTION

The ctermid() function generates a string, that, when used as a pathname, refers to the current controlling terminal of the calling process.

If buf is the NULL pointer, a pointer to a static area is returned. Otherwise, the pathname is copied into the memory referenced by buf. The argument buf is assumed to be at least L_ctermid (as defined in the include file <stdio.h>) bytes long.

The ctermid_r() function provides the same functionality as ctermid() except that if buf is a NULL pointer, NULL is returned.

If no suitable lookup of the controlling terminal name can be performed, this implementation returns ‘/dev/tty’.

RETURN VALUES

Upon successful completion, a non-NULL pointer is returned. Otherwise, a NULL pointer is returned and the global variable errno is set to indicate the error.

ERRORS

The current implementation detects no error conditions.

SEE ALSO

ttyname(3)

STANDARDS

The ctermid() function conforms to IEEE Std 1003.1-1988 (“POSIX.1”).

BUGS

By default the ctermid() function writes all information to an internal static object. Subsequent calls to ctermid() will modify the same object.