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: src/lib/libc/sys/getsid.2,v 1.3.2.5 2001/12/14 18:34:00 ru Exp $ 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.Fo getsid 38.Fa "pid_t pid" 39.Fc 40.Sh DESCRIPTION 41The session ID of the process identified by 42.Fa pid 43is returned by 44.Fn getsid . 45If 46.Fa pid 47is zero, 48.Fn getsid 49returns the session ID of the current process. 50.Sh RETURN VALUES 51Upon successful completion, the function 52.Fn getsid 53returns the session ID of 54the specified process; otherwise, it returns a value of -1 and 55sets errno to indicate an error. 56.Sh ERRORS 57The 58.Fn getsid 59system call will fail if: 60.Bl -tag -width Er 61.\" ========== 62.It Bq Er ESRCH 63There is no process with a process ID equal to 64.Fa pid . 65.El 66.Pp 67Note that an implementation may restrict this function call to 68processes within the same session ID as the calling process. 69.Sh SEE ALSO 70.Xr getpgid 2 , 71.Xr getpgrp 2 , 72.Xr setpgid 2 , 73.Xr setsid 2 , 74.Xr termios 4 75.Sh HISTORY 76The 77.Fn getsid 78function call appeared in 79.Fx 3.0 . 80The 81.Fn getsid 82function call is derived from its usage in 83.At V . 84