1.\" $NetBSD: setpgid.2,v 1.24 2022/03/16 00:50:40 dholland Exp $ 2.\" 3.\" Copyright (c) 1980, 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.\" @(#)setpgid.2 8.1 (Berkeley) 6/4/93 31.\" 32.Dd March 15, 2022 33.Dt SETPGID 2 34.Os 35.Sh NAME 36.Nm setpgid , 37.Nm setpgrp 38.Nd set process group 39.Sh LIBRARY 40.Lb libc 41.Sh SYNOPSIS 42.In unistd.h 43.Ft int 44.Fn setpgid "pid_t pid" "pid_t pgrp" 45.Ft int 46.Fn setpgrp "pid_t pid" "pid_t pgrp" 47.Sh DESCRIPTION 48.Fn setpgid 49sets the process group of the specified process 50.Ar pid 51to the specified 52.Ar pgrp . 53If 54.Ar pid 55is zero, then the call applies to the current process. 56If 57.Ar pgrp 58is zero, then the process id of the process specified by 59.Ar pid 60is used instead. 61.Pp 62If the invoker is not the super-user, then the affected process 63must have the same effective user-id as the invoker or be a descendant 64of the invoking process. 65.Pp 66In general to set the process group of a newly forked subprocess, both 67the child and parent processes should call 68.Fn setpgid 69to ensure that the process group change takes effect in a timely 70fashion. 71One call will succeed and the other will fail, depending on process 72scheduling. 73.Sh RETURN VALUES 74.Fn setpgid 75returns 0 when the operation was successful. 76If the request failed, \-1 is returned and the global variable 77.Va errno 78indicates the reason. 79.Sh COMPATIBILITY 80.Fn setpgrp 81is identical to 82.Fn setpgid , 83and is retained for calling convention compatibility with historical 84versions of 85.Bx . 86.Sh ERRORS 87.Fn setpgid 88will fail and the process group will not be altered if: 89.Bl -tag -width Er 90.It Bq Er EACCES 91The value of the 92.Fa pid 93argument matches the process ID of a child process of the calling process, 94and the child process has successfully executed one of the exec functions. 95.It Bq Er EINVAL 96The value of the 97.Fa pgrp 98argument is less than zero. 99.It Bq Er EPERM 100The effective user ID of the requested process is different 101from that of the caller and the process is not a descendant 102of the calling process. 103.It Bq Er ESRCH 104The value of the 105.Fa pid 106argument does not match the process ID of the calling process or of a 107child process of the calling process. 108.El 109.Sh SEE ALSO 110.Xr getpgrp 2 111.Sh STANDARDS 112The 113.Fn setpgid 114function conforms to 115.St -p1003.1-90 . 116