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.\" $DragonFly: src/lib/libc/sys/setsid.2,v 1.2 2003/06/17 04:26:47 dillon Exp $ 35.\" 36.Dd June 4, 1993 37.Dt SETSID 2 38.Os 39.Sh NAME 40.Nm setsid 41.Nd create session and set process group ID 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.In unistd.h 46.Ft pid_t 47.Fn setsid void 48.Sh DESCRIPTION 49The 50.Fn setsid 51function creates a new session. 52The calling process is the session leader of the new session, is the 53process group leader of a new process group and has no controlling 54terminal. 55The calling process is the only process in either the session or the 56process group. 57.Sh RETURN VALUES 58Upon successful completion, the 59.Fn setsid 60function returns the value of the process group ID of the new process 61group, which is the same as the process ID of the calling process. 62If an error occurs, 63.Fn setsid 64returns -1 and the global variable 65.Va errno 66is set to indicate the error. 67.Sh ERRORS 68The 69.Fn setsid 70function will fail if: 71.Bl -tag -width Er 72.It Bq Er EPERM 73The calling process is already a process group leader, or the process 74group ID of a process other than the calling process matches the process 75ID of the calling process. 76.El 77.Sh SEE ALSO 78.Xr setpgid 2 , 79.Xr tcgetpgrp 3 , 80.Xr tcsetpgrp 3 81.Sh STANDARDS 82The 83.Fn setsid 84function is expected to be compliant with the 85.St -p1003.1-90 86specification. 87