1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
|
.\" Copyright (c) 1983, 1991 Regents of the University of California.
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\" must display the following acknowledgement:
.\" This product includes software developed by the University of
.\" California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\" may be used to endorse or promote products derived from this software
.\" without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" @(#)getpgrp.2 6.4 (Berkeley) 3/10/91
.\"
.\" Modified Sat Jul 24 01:15:33 1993 by Rik Faith <faith@cs.unc.edu>
.\" Modified 15 April 1995 by Michael Chastain <mec@shell.portal.com>:
.\" Added 'getpgid'.
.\" Modified 21 July 1996 by Andries Brouwer <aeb@cwi.nl>
.\" Modified Wed Nov 6 04:02:50 1996 by Eric S. Raymond <esr@thyrsus.com>
.\" FIXME -- error conditions need to be better documented, see kernel
.\"
.TH SETPGID 2 "15 April 1995" "Linux 1.2.4" "Linux Programmer's Manual"
.SH NAME
setpgid, getpgid, setpgrp, getpgrp \- set/get process group
.SH SYNOPSIS
.B #include <unistd.h>
.sp
.BI "int setpgid(pid_t " pid ", pid_t " pgid );
.br
.BI "pid_t getpgid(pid_t " pid );
.br
.B int setpgrp(void);
.br
.B pid_t getpgrp(void);
.SH DESCRIPTION
.B setpgid
sets the process group ID of the process specified by
.I pid
to
.IR pgid .
If
.I pid
is zero, the process ID of the current process is used. If
.I pgid
is zero, the process ID of the process specified by
.I pid
is used.
.B getpgid
returns the process group ID of the process specified by
.IR pid .
If
.I pid
is zero, the process ID of the current process is used.
In the Linux DLL 4.4.1 library,
.B setpgrp
simply calls
.BR setpgid(0,0) .
.B getpgrp
is equivalent to
.BR getpgid(0) .
Process groups are used for distribution of signals, and by terminals to
arbitrate requests for their input: processes that have the same process
group as the terminal are foreground and may read, while others will block
with a signal if they attempt to read.
These calls are thus used by programs such as
.BR csh (1)
to create process groups in implementing job control. The
.B TIOCGPGRP
and
.B TIOCSPGRP
calls described in
.BR termios (4)
are used to get/set the process group of the control terminal.
.SH "RETURN VALUE"
On success,
.BR setpgid " and " setpgrp
return zero. On error, \-1 is returned, and
.I errno
is set appropriately.
.B getpgid
returns a process group on success.
On error, \-1 is returned, and
.I errno
is set appropriately.
.B getpgrp
always returns the current process group.
.SH ERRORS
.TP 0.8i
.B EINVAL
.I pgid
is less than 0.
.TP
.B EPERM
Various permission violations.
.TP
.B ESRCH
.I pid
does not match any process.
.SH "CONFORMING TO"
SVr4, POSIX, 4.4BSD.
.SH "CONFORMING TO"
The functions
.B setpgid
and
.B getpgrp
conform to POSIX.1.
The function
.B setpgrp
is from BSD 4.2.
The function
.B getpgid
conforms to SVr4.
.SH "SEE ALSO"
.BR getuid (2),
.BR setsid (2),
.BR tcsetpgrp (3),
.BR termios (4)
|
