1.\" Copyright (c) 1997 Peter Wemm <[email protected]> 2.\" 3.\" Redistribution and use in source and binary forms, with or without 4.\" modification, are permitted provided that the following conditions 5.\" are met: 6.\" 1. Redistributions of source code must retain the above copyright 7.\" notice, this list of conditions and the following disclaimer. 8.\" 2. Redistributions in binary form must reproduce the above copyright 9.\" notice, this list of conditions and the following disclaimer in the 10.\" documentation and/or other materials provided with the distribution. 11.\" 12.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 13.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 14.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 15.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 16.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 17.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 18.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 19.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 20.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 21.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 22.\" SUCH DAMAGE. 23.\" 24.\" $FreeBSD$ 25.\" 26.Dd August 19, 1997 27.Dt GETSID 2 28.Os 29.Sh NAME 30.Nm getsid 31.Nd get process session 32.Sh LIBRARY 33.Lb libc 34.Sh SYNOPSIS 35.In unistd.h 36.Ft pid_t 37.Fn getsid "pid_t pid" 38.Sh DESCRIPTION 39The session ID of the process identified by 40.Fa pid 41is returned by 42.Fn getsid . 43If 44.Fa pid 45is zero, 46.Fn getsid 47returns the session ID of the current process. 48.Sh RETURN VALUES 49Upon successful completion, the 50.Fn getsid 51system call 52returns the session ID of 53the specified process; otherwise, it returns a value of -1 and 54sets errno to indicate an error. 55.Sh ERRORS 56The 57.Fn getsid 58system call 59will succeed unless: 60.Bl -tag -width Er 61.It Bq Er ESRCH 62if there is no process with a process ID equal to 63.Fa pid . 64.El 65.Pp 66Note that an implementation may restrict this system call to 67processes within the same session ID as the calling process. 68.Sh SEE ALSO 69.Xr getpgid 2 , 70.Xr getpgrp 2 , 71.Xr setpgid 2 , 72.Xr setsid 2 , 73.Xr termios 4 74.Sh HISTORY 75The 76.Fn getsid 77system call appeared in 78.Fx 3.0 . 79The 80.Fn getsid 81system call is derived from its usage in 82.At V . 83