1.\" Copyright (c) 1990, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)ctermid.3 8.1 (Berkeley) 6/4/93 33.\" $FreeBSD: src/lib/libc/gen/ctermid.3,v 1.5.2.4 2003/03/15 15:11:05 trhodes Exp $ 34.\" 35.Dd June 4, 1993 36.Dt CTERMID 3 37.Os 38.Sh NAME 39.Nm ctermid 40.Nd generate terminal pathname 41.Sh LIBRARY 42.Lb libc 43.Sh SYNOPSIS 44.In stdio.h 45.Ft char * 46.Fn ctermid "char *buf" 47.Ft char * 48.Fn ctermid_r "char *buf" 49.Sh DESCRIPTION 50The 51.Fn ctermid 52function generates a string, that, when used as a pathname, refers to 53the current controlling terminal of the calling process. 54.Pp 55If 56.Fa buf 57is the 58.Dv NULL 59pointer, a pointer to a static area is returned. 60Otherwise, the pathname is copied into the memory referenced by 61.Fa buf . 62The argument 63.Fa buf 64is assumed to be at least 65.Dv L_ctermid 66(as defined in the include 67file 68.Aq Pa stdio.h ) 69bytes long. 70.Pp 71The 72.Fn ctermid_r 73function 74provides the same functionality as 75.Fn ctermid 76except that if 77.Fa buf 78is a 79.Dv NULL 80pointer, 81.Dv NULL 82is returned. 83.Pp 84The current implementation simply returns 85.Ql /dev/tty . 86.Sh RETURN VALUES 87Upon successful completion, a 88.Pf non- Dv NULL 89pointer is returned. 90Otherwise, a 91.Dv NULL 92pointer is returned and the global variable 93.Va errno 94is set to indicate the error. 95.Sh ERRORS 96The current implementation detects no error conditions. 97.Sh SEE ALSO 98.Xr ttyname 3 99.Sh STANDARDS 100The 101.Fn ctermid 102function conforms to 103.St -p1003.1-88 . 104.Sh BUGS 105By default the 106.Fn ctermid 107function 108writes all information to an internal static object. 109Subsequent calls to 110.Fn ctermid 111will modify the same object. 112