1.\" $OpenBSD: setsid.2,v 1.10 1999/07/02 16:57:49 aaron Exp $ 2.\" $NetBSD: setsid.2,v 1.3 1995/10/12 15:41:13 jtc Exp $ 3.\" 4.\" Copyright (c) 1991, 1993 5.\" The Regents of the University of California. All rights reserved. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. All advertising materials mentioning features or use of this software 16.\" must display the following acknowledgement: 17.\" This product includes software developed by the University of 18.\" California, Berkeley and its contributors. 19.\" 4. Neither the name of the University nor the names of its contributors 20.\" may be used to endorse or promote products derived from this software 21.\" without specific prior written permission. 22.\" 23.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33.\" SUCH DAMAGE. 34.\" 35.\" @(#)setsid.2 8.1 (Berkeley) 6/4/93 36.\" 37.Dd June 4, 1993 38.Dt SETSID 2 39.Os 40.Sh NAME 41.Nm setsid 42.Nd create session and set process group ID 43.Sh SYNOPSIS 44.Fd #include <unistd.h> 45.Ft pid_t 46.Fn setsid "void" 47.Sh DESCRIPTION 48The 49.Nm setsid 50function creates a new session. 51The calling process is the session leader of the new session, is the 52process group leader of a new process group and has no controlling 53terminal. 54The calling process is the only process in either the session or the 55process group. 56.Pp 57Upon successful completion, the 58.Nm setsid 59function returns the value of the process group ID of the new process 60group, which is the same as the process ID of the calling process. 61.Sh ERRORS 62If an error occurs, 63.Nm setsid 64returns \-1 and the global variable 65.Va errno 66is set to indicate the error, as follows: 67.Bl -tag -width Er 68.It Bq Er EPERM 69The calling process is already a process group leader, or the process 70group ID of a process other than the calling process matches the process 71ID of the calling process. 72.El 73.Sh SEE ALSO 74.Xr getsid 2 , 75.Xr setpgid 2 , 76.Xr tcgetpgrp 3 , 77.Xr tcsetpgrp 3 78.Sh STANDARDS 79The 80.Nm setsid 81function is expected to be compliant with the 82.St -p1003.1-88 83specification. 84