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.\" 30.Dd June 4, 1993 31.Dt SETSID 2 32.Os 33.Sh NAME 34.Nm setsid 35.Nd create session and set process group ID 36.Sh LIBRARY 37.Lb libc 38.Sh SYNOPSIS 39.In unistd.h 40.Ft pid_t 41.Fn setsid void 42.Sh DESCRIPTION 43The 44.Fn setsid 45system call creates a new session. 46The calling process is the session leader of the new session, is the 47process group leader of a new process group and has no controlling 48terminal. 49The calling process is the only process in either the session or the 50process group. 51.Sh RETURN VALUES 52Upon successful completion, the 53.Fn setsid 54system call returns the value of the process group ID of the new process 55group, which is the same as the process ID of the calling process. 56If an error occurs, 57.Fn setsid 58returns -1 and the global variable 59.Va errno 60is set to indicate the error. 61.Sh ERRORS 62The 63.Fn setsid 64system call will fail if: 65.Bl -tag -width Er 66.It Bq Er EPERM 67The calling process is already a process group leader, or the process 68group ID of a process other than the calling process matches the process 69ID of the calling process. 70.El 71.Sh SEE ALSO 72.Xr setpgid 2 , 73.Xr tcgetpgrp 3 , 74.Xr tcsetpgrp 3 75.Sh STANDARDS 76The 77.Fn setsid 78system call is expected to be compliant with the 79.St -p1003.1-90 80specification. 81