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. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)setsid.2 8.1 (Berkeley) 6/4/93 29.\" $FreeBSD: src/lib/libc/sys/setsid.2,v 1.10.2.2 2001/12/14 18:34:01 ru Exp $ 30.\" $DragonFly: src/lib/libc/sys/setsid.2,v 1.2 2003/06/17 04:26:47 dillon Exp $ 31.\" 32.Dd June 4, 1993 33.Dt SETSID 2 34.Os 35.Sh NAME 36.Nm setsid 37.Nd create session and set process group ID 38.Sh LIBRARY 39.Lb libc 40.Sh SYNOPSIS 41.In unistd.h 42.Ft pid_t 43.Fn setsid void 44.Sh DESCRIPTION 45The 46.Fn setsid 47function creates a new session. 48The calling process is the session leader of the new session, is the 49process group leader of a new process group and has no controlling 50terminal. 51The calling process is the only process in either the session or the 52process group. 53.Sh RETURN VALUES 54Upon successful completion, the 55.Fn setsid 56function returns the value of the process group ID of the new process 57group, which is the same as the process ID of the calling process. 58If an error occurs, 59.Fn setsid 60returns -1 and the global variable 61.Va errno 62is set to indicate the error. 63.Sh ERRORS 64The 65.Fn setsid 66function will fail if: 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 setpgid 2 , 75.Xr tcgetpgrp 3 , 76.Xr tcsetpgrp 3 77.Sh STANDARDS 78The 79.Fn setsid 80function is expected to be compliant with the 81.St -p1003.1-90 82specification. 83