1.\" $NetBSD: tcgetsid.3,v 1.6 2019/12/19 16:12:21 leot Exp $ 2.\" 3.\" Copyright (c) 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.\" @(#)tcgetpgrp.3 8.1 (Berkeley) 6/4/93 31.\" 32.Dd December 19, 2019 33.Dt TCGETSID 3 34.Os 35.Sh NAME 36.Nm tcgetsid 37.Nd get session ID associated with a controlling terminal 38.Sh LIBRARY 39.Lb libc 40.Sh SYNOPSIS 41.In termios.h 42.Ft pid_t 43.Fn tcgetsid "int fd" 44.Sh DESCRIPTION 45The 46.Nm tcgetsid 47function returns the value of the session ID associated with the specified 48controlling terminal device. 49The session ID is defined as the process group ID of the session leader. 50.Sh ERRORS 51If an error occurs, 52.Nm tcgetsid 53returns -1 and the global variable 54.Va errno 55is set to indicate the error, as follows: 56.Bl -tag -width Er 57.It Bq Er EBADF 58The 59.Fa fd 60argument is not a valid file descriptor. 61.It Bq Er ENOTTY 62The calling process does not have a controlling terminal or the 63underlying terminal device represented by 64.Fa fd 65is not the controlling terminal. 66.El 67.Sh SEE ALSO 68.Xr getsid 2 , 69.Xr setsid 2 , 70.Xr tcgetpgrp 3 71.Sh STANDARDS 72The 73.Nm tcgetsid 74function conforms to 75.St -xpg4.2 . 76