.\"	$NetBSD: getsid.2,v 1.9 2004/05/13 10:20:58 wiz Exp $
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.\"     @(#)getpgrp.2	8.1 (Berkeley) 6/4/93
.\"
.Dd February 13, 1998
.Dt GETSID 2
.Os
.Sh NAME
.Nm getsid
.Nd get session ID
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In unistd.h
.Ft pid_t
.Fn getsid "pid_t pid"
.Sh DESCRIPTION
The
.Nm
function returns the session ID of the process specified by
.Ar pid .
If
.Ar pid
is 0, the session ID of the calling process is returned.
The session ID is defined as the process group ID of the
process that is the session leader.
.Sh ERRORS
If an error occurs,
.Nm
returns \-1 and the global variable
.Va errno
is set to indicate the error, as follows:
.Bl -tag -width Er
.It Bq Er ESRCH
No process can be found corresponding to that specified by
.Ar pid .
.El
.Sh SEE ALSO
.Xr getpgid 2 ,
.Xr termios 4
.Sh STANDARDS
The
.Fn getsid
function conforms to
.St -xpg4.2 .