1.\" Copyright (c) 1983, 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.\" @(#)getpgrp.2 8.1 (Berkeley) 6/4/93 33.\" $FreeBSD: src/lib/libc/sys/getpgrp.2,v 1.11.2.6 2001/12/14 18:34:00 ru Exp $ 34.\" 35.Dd June 4, 1993 36.Dt GETPGRP 2 37.Os 38.Sh NAME 39.Nm getpgid , 40.Nm getpgrp 41.Nd get process group 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.In unistd.h 46.Ft pid_t 47.Fo getpgid 48.Fa "pid_t pid" 49.Fc 50.Ft pid_t 51.Fo getpgrp 52.Fa void 53.Fc 54.Sh DESCRIPTION 55The process group of the current process is returned by 56.Fn getpgrp . 57The process group of the process identified by 58.Fa pid 59is returned by 60.Fn getpgid . 61If 62.Fa pid 63is zero, 64.Fn getpgid 65returns the process group of the current process. 66.Pp 67Process groups are used for distribution of signals, and 68by terminals to arbitrate requests for their input: processes 69that have the same process group as the terminal are foreground 70and may read, while others will block with a signal if they attempt 71to read. 72.Pp 73This call is thus used by programs such as 74.Xr csh 1 75to create 76process groups 77in implementing job control. 78The 79.Fn tcgetpgrp 80and 81.Fn tcsetpgrp 82calls 83are used to get/set the process group of the control terminal. 84.Sh RETURN VALUES 85The 86.Fn getpgrp 87call always succeeds. 88Upon successful completion, the 89.Fn getpgid 90call returns the process group of the specified process; 91otherwise, it returns a value of \-1 and sets 92.Va errno 93to indicate the error. 94.Sh ERRORS 95.Fn getpgid 96will succeed unless: 97.Bl -tag -width Er 98.\" ========== 99.It Bq Er ESRCH 100There is no process whose process ID equals 101.Fa pid . 102.El 103.Sh SEE ALSO 104.Xr getsid 2 , 105.Xr setpgid 2 , 106.Xr termios 4 107.Sh HISTORY 108The 109.Fn getpgrp 110function call appeared in 111.Bx 4.0 . 112The 113.Fn getpgid 114function call is derived from its usage in System V Release 4. 115.Sh STANDARDS 116The 117.Fn getpgrp 118function call is expected to conform to 119.St -p1003.1-90 . 120.Sh COMPATIBILITY 121This version of 122.Fn getpgrp 123differs from past Berkeley versions by not taking a 124.Fa "pid_t pid" 125argument. 126This incompatibility is required by 127.St -p1003.1-90 . 128.Pp 129From the 130.St -p1003.1-90 131Rationale: 132.Pp 133.Bx 4.3 134provides a 135.Fn getpgrp 136function that returns the process group ID for a specified process. 137Although this function is used to support job control, all known 138job-control shells always specify the calling process with this 139function. 140Thus, the simpler 141.At V 142.Fn getpgrp 143suffices, and the added complexity of the 144.Bx 4.3 145.Fn getpgrp 146has been omitted from POSIX.1. 147The old functionality is available from the 148.Fn getpgid 149function. 150