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.\" 30.Dd October 1, 2011 31.Dt CTERMID 3 32.Os 33.Sh NAME 34.Nm ctermid 35.Nd generate terminal pathname 36.Sh LIBRARY 37.Lb libc 38.Sh SYNOPSIS 39.In stdio.h 40.Ft char * 41.Fn ctermid "char *buf" 42.Ft char * 43.Fn ctermid_r "char *buf" 44.Sh DESCRIPTION 45The 46.Fn ctermid 47function generates a string, that, when used as a pathname, refers to 48the current controlling terminal of the calling process. 49.Pp 50If 51.Fa buf 52is the 53.Dv NULL 54pointer, a pointer to a static area is returned. 55Otherwise, the pathname is copied into the memory referenced by 56.Fa buf . 57The argument 58.Fa buf 59is assumed to be at least 60.Dv L_ctermid 61(as defined in the include 62file 63.In stdio.h ) 64bytes long. 65.Pp 66The 67.Fn ctermid_r 68function 69provides the same functionality as 70.Fn ctermid 71except that if 72.Fa buf 73is a 74.Dv NULL 75pointer, 76.Dv NULL 77is returned. 78.Pp 79If no suitable lookup of the controlling terminal name can be performed, 80this implementation returns 81.Ql /dev/tty . 82.Sh RETURN VALUES 83Upon successful completion, a 84.Pf non- Dv NULL 85pointer is returned. 86Otherwise, a 87.Dv NULL 88pointer is returned and the global variable 89.Va errno 90is set to indicate the error. 91.Sh ERRORS 92The current implementation detects no error conditions. 93.Sh SEE ALSO 94.Xr ttyname 3 95.Sh STANDARDS 96The 97.Fn ctermid 98function conforms to 99.St -p1003.1-88 . 100.Sh BUGS 101By default the 102.Fn ctermid 103function 104writes all information to an internal static object. 105Subsequent calls to 106.Fn ctermid 107will modify the same object. 108