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.\" 4. 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.\" $FreeBSD$ 30.\" 31.Dd October 1, 2011 32.Dt CTERMID 3 33.Os 34.Sh NAME 35.Nm ctermid 36.Nd generate terminal pathname 37.Sh LIBRARY 38.Lb libc 39.Sh SYNOPSIS 40.In stdio.h 41.Ft char * 42.Fn ctermid "char *buf" 43.Ft char * 44.Fn ctermid_r "char *buf" 45.Sh DESCRIPTION 46The 47.Fn ctermid 48function generates a string, that, when used as a pathname, refers to 49the current controlling terminal of the calling process. 50.Pp 51If 52.Fa buf 53is the 54.Dv NULL 55pointer, a pointer to a static area is returned. 56Otherwise, the pathname is copied into the memory referenced by 57.Fa buf . 58The argument 59.Fa buf 60is assumed to be at least 61.Dv L_ctermid 62(as defined in the include 63file 64.In stdio.h ) 65bytes long. 66.Pp 67The 68.Fn ctermid_r 69function 70provides the same functionality as 71.Fn ctermid 72except that if 73.Fa buf 74is a 75.Dv NULL 76pointer, 77.Dv NULL 78is returned. 79.Pp 80If no suitable lookup of the controlling terminal name can be performed, 81this implementation 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