.\" Copyright (c) 1990, 1991, 1993 .\" The Regents of the University of California. All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 4. Neither the name of the University nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" @(#)ctermid.3 8.1 (Berkeley) 6/4/93 .\" $FreeBSD: src/lib/libc/gen/ctermid.3,v 1.12 2007/01/09 00:27:53 imp Exp $ .\" .Dd June 4, 1993 .Dt CTERMID 3 .Os .Sh NAME .Nm ctermid , .Nm ctermid_r .Nd generate terminal pathname .Sh LIBRARY .Lb libc .Sh SYNOPSIS .In stdio.h .Ft char * .Fn ctermid "char *s" .Ft char * .Fn ctermid_r "char *s" .Sh DESCRIPTION The .Fn ctermid function generates a string that, when used as a pathname, refers to the current controlling terminal of the calling process. .Pp If .Fa s is the .Dv NULL pointer, a pointer to a static area is returned. Otherwise, the pathname is copied into the memory referenced by .Fa s . The argument .Fa s is assumed to be at least .Dv L_ctermid (as defined in the include file .In stdio.h ) bytes long. .Pp The .Fn ctermid_r function provides the same functionality as .Fn ctermid , except that if .Fa s is a .Dv NULL pointer, .Dv NULL is returned. .Pp The current implementation simply returns .Ql /dev/tty . .Sh RETURN VALUES Upon successful completion, a .Pf non- Dv NULL pointer is returned. Otherwise, a .Dv NULL pointer is returned and the global variable .Va errno is set to indicate the error. .Sh ERRORS The current implementation detects no error conditions. .Sh SEE ALSO .Xr ttyname 3 .Sh STANDARDS The .Fn ctermid function conforms to .St -p1003.1-88 . .Sh BUGS By default the .Fn ctermid function writes all information to an internal static object. Subsequent calls to .Fn ctermid will modify the same object.