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.Dd June 4, 1993 29.Dt SETSID 2 30.Os 31.Sh NAME 32.Nm setsid 33.Nd create session and set process group ID 34.Sh LIBRARY 35.Lb libc 36.Sh SYNOPSIS 37.In unistd.h 38.Ft pid_t 39.Fn setsid void 40.Sh DESCRIPTION 41The 42.Fn setsid 43system call creates a new session. 44The calling process is the session leader of the new session, is the 45process group leader of a new process group and has no controlling 46terminal. 47The calling process is the only process in either the session or the 48process group. 49.Sh RETURN VALUES 50Upon successful completion, the 51.Fn setsid 52system call returns the value of the process group ID of the new process 53group, which is the same as the process ID of the calling process. 54If an error occurs, 55.Fn setsid 56returns -1 and the global variable 57.Va errno 58is set to indicate the error. 59.Sh ERRORS 60The 61.Fn setsid 62system call will fail if: 63.Bl -tag -width Er 64.It Bq Er EPERM 65The calling process is already a process group leader, or the process 66group ID of a process other than the calling process matches the process 67ID of the calling process. 68.El 69.Sh SEE ALSO 70.Xr setpgid 2 , 71.Xr tcgetpgrp 3 , 72.Xr tcsetpgrp 3 73.Sh STANDARDS 74The 75.Fn setsid 76system call is expected to be compliant with the 77.St -p1003.1-90 78specification. 79