1.\" $OpenBSD: getsid.2,v 1.12 2015/09/10 17:55:21 schwarze Exp $ 2.\" 3.\" Copyright (c) 1997 Peter Wemm <peter@freebsd.org> 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24.\" SUCH DAMAGE. 25.\" 26.\" 27.Dd $Mdocdate: September 10 2015 $ 28.Dt GETSID 2 29.Os 30.Sh NAME 31.Nm getsid 32.Nd get process session 33.Sh SYNOPSIS 34.In unistd.h 35.Ft pid_t 36.Fn getsid "pid_t pid" 37.Sh DESCRIPTION 38The session ID of the process identified by 39.Fa pid 40is returned by 41.Fn getsid . 42If 43.Fa pid 44is zero, 45.Fn getsid 46returns the session ID of the current process. 47.Sh RETURN VALUES 48Upon successful completion, the function 49.Fn getsid 50returns the session ID of 51the specified process; otherwise, it returns a value of \-1 and 52sets 53.Va errno 54to indicate an error. 55.Sh ERRORS 56.Fn getsid 57will succeed unless: 58.Bl -tag -width Er 59.It Bq Er EPERM 60The current process and the process 61.Fa pid 62are not in the same session. 63.It Bq Er ESRCH 64There is no process with a process ID equal to 65.Fa pid . 66.El 67.Sh SEE ALSO 68.Xr getpgid 2 , 69.Xr getpgrp 2 , 70.Xr setpgid 2 , 71.Xr setsid 2 , 72.Xr termios 4 73.Sh STANDARDS 74.Fn getsid 75conforms to 76.St -p1003.1-2008 . 77.Sh HISTORY 78The 79.Fn getsid 80function call is derived from its usage in 81.At V , 82and is mandated by 83.St -xpg4 . 84