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.\" $DragonFly: src/lib/libc/gen/ctermid.3,v 1.3 2006/05/26 19:39:36 swildner Exp $ 35.\" 36.Dd June 4, 1993 37.Dt CTERMID 3 38.Os 39.Sh NAME 40.Nm ctermid 41.Nd generate terminal pathname 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.In stdio.h 46.Ft char * 47.Fn ctermid "char *buf" 48.Ft char * 49.Fn ctermid_r "char *buf" 50.Sh DESCRIPTION 51The 52.Fn ctermid 53function generates a string, that, when used as a pathname, refers to 54the current controlling terminal of the calling process. 55.Pp 56If 57.Fa buf 58is the 59.Dv NULL 60pointer, a pointer to a static area is returned. 61Otherwise, the pathname is copied into the memory referenced by 62.Fa buf . 63The argument 64.Fa buf 65is assumed to be at least 66.Dv L_ctermid 67(as defined in the include 68file 69.In stdio.h ) 70bytes long. 71.Pp 72The 73.Fn ctermid_r 74function 75provides the same functionality as 76.Fn ctermid 77except that if 78.Fa buf 79is a 80.Dv NULL 81pointer, 82.Dv NULL 83is returned. 84.Pp 85The current implementation simply returns 86.Ql /dev/tty . 87.Sh RETURN VALUES 88Upon successful completion, a 89.Pf non- Dv NULL 90pointer is returned. 91Otherwise, a 92.Dv NULL 93pointer is returned and the global variable 94.Va errno 95is set to indicate the error. 96.Sh ERRORS 97The current implementation detects no error conditions. 98.Sh SEE ALSO 99.Xr ttyname 3 100.Sh STANDARDS 101The 102.Fn ctermid 103function conforms to 104.St -p1003.1-88 . 105.Sh BUGS 106By default the 107.Fn ctermid 108function 109writes all information to an internal static object. 110Subsequent calls to 111.Fn ctermid 112will modify the same object. 113