1.\" Copyright (c) 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)setsid.2 8.1 (Berkeley) 6/4/93 33.\" $FreeBSD: src/lib/libc/sys/setsid.2,v 1.10.2.2 2001/12/14 18:34:01 ru Exp $ 34.\" 35.Dd June 4, 1993 36.Dt SETSID 2 37.Os 38.Sh NAME 39.Nm setsid 40.Nd create session and set process group ID 41.Sh LIBRARY 42.Lb libc 43.Sh SYNOPSIS 44.In unistd.h 45.Ft pid_t 46.Fn setsid void 47.Sh DESCRIPTION 48The 49.Fn 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.Sh RETURN VALUES 57Upon successful completion, the 58.Fn 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. 61If an error occurs, 62.Fn setsid 63returns -1 and the global variable 64.Va errno 65is set to indicate the error. 66.Sh ERRORS 67The 68.Fn setsid 69function will fail if: 70.Bl -tag -width Er 71.It Bq Er EPERM 72The calling process is already a process group leader, or the process 73group ID of a process other than the calling process matches the process 74ID of the calling process. 75.El 76.Sh SEE ALSO 77.Xr setpgid 2 , 78.Xr tcgetpgrp 3 , 79.Xr tcsetpgrp 3 80.Sh STANDARDS 81The 82.Fn setsid 83function is expected to be compliant with the 84.St -p1003.1-90 85specification. 86