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. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)ctermid.3 8.1 (Berkeley) 6/4/93 29.\" $FreeBSD: src/lib/libc/gen/ctermid.3,v 1.5.2.4 2003/03/15 15:11:05 trhodes Exp $ 30.\" $DragonFly: src/lib/libc/gen/ctermid.3,v 1.3 2006/05/26 19:39:36 swildner Exp $ 31.\" 32.Dd June 4, 1993 33.Dt CTERMID 3 34.Os 35.Sh NAME 36.Nm ctermid 37.Nd generate terminal pathname 38.Sh LIBRARY 39.Lb libc 40.Sh SYNOPSIS 41.In stdio.h 42.Ft char * 43.Fn ctermid "char *buf" 44.Ft char * 45.Fn ctermid_r "char *buf" 46.Sh DESCRIPTION 47The 48.Fn ctermid 49function generates a string, that, when used as a pathname, refers to 50the current controlling terminal of the calling process. 51.Pp 52If 53.Fa buf 54is the 55.Dv NULL 56pointer, a pointer to a static area is returned. 57Otherwise, the pathname is copied into the memory referenced by 58.Fa buf . 59The argument 60.Fa buf 61is assumed to be at least 62.Dv L_ctermid 63(as defined in the include 64file 65.In stdio.h ) 66bytes long. 67.Pp 68The 69.Fn ctermid_r 70function 71provides the same functionality as 72.Fn ctermid 73except that if 74.Fa buf 75is a 76.Dv NULL 77pointer, 78.Dv NULL 79is returned. 80.Pp 81The current implementation simply returns 82.Ql /dev/tty . 83.Sh RETURN VALUES 84Upon successful completion, a 85.Pf non- Dv NULL 86pointer is returned. 87Otherwise, a 88.Dv NULL 89pointer is returned and the global variable 90.Va errno 91is set to indicate the error. 92.Sh ERRORS 93The current implementation detects no error conditions. 94.Sh SEE ALSO 95.Xr ttyname 3 96.Sh STANDARDS 97The 98.Fn ctermid 99function conforms to 100.St -p1003.1-88 . 101.Sh BUGS 102By default the 103.Fn ctermid 104function 105writes all information to an internal static object. 106Subsequent calls to 107.Fn ctermid 108will modify the same object. 109