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.\" Hey Emacs! This file is -*- nroff -*- source.
.\"
.\" Copyright 1993 Rickard E. Faith (faith@cs.unc.edu)
.\"
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
.\"
.\" Permission is granted to copy and distribute modified versions of this
.\" manual under the conditions for verbatim copying, provided that the
.\" entire resulting derived work is distributed under the terms of a
.\" permission notice identical to this one
.\"
.\" Since the Linux kernel and libraries are constantly changing, this
.\" manual page may be incorrect or out-of-date. The author(s) assume no
.\" responsibility for errors or omissions, or for damages resulting from
.\" the use of the information contained herein. The author(s) may not
.\" have taken the same level of care in the production of this manual,
.\" which is licensed free of charge, as they might when working
.\" professionally.
.\"
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
.\"
.\" Modified Thu Oct 31 12:04:29 1996 by Eric S. Raymond <esr@thyrsus.com>
.TH GETGROUPS 2 "10 December 1997" "Linux 2.0.32" "Linux Programmer's Manual"
.SH NAME
getgroups, setgroups \- get/set list of supplementary group IDs
.SH SYNOPSIS
.B #include <unistd.h>
.sp
.BI "int getgroups(int " size ", gid_t " list []);
.sp 2
.B #define _BSD_SOURCE
.br
.B #include <grp.h>
.sp
.BI "int setgroups(size_t " size ", const gid_t *" list );
.SH DESCRIPTION
.TP
.B getgroups
Up to
.I size
supplementary groups are returned in
.IR list .
If
.I size
is zero,
.I list
is not modified, but the total number of supplementary groups for the
process is returned.
.TP
.B setgroups
Sets the supplementary groups for the process. Only the super-user may use
this function.
.SH "RETURN VALUE"
.TP
.B getgroups
On success, the number of supplementary group IDs is returned.
On error, \-1 is returned, and
.I errno
is set appropriately.
.TP
.B setgroups
On success, zero is returned. On error, \-1 is returned, and
.I errno
is set appropriately.
.SH ERRORS
.TP
.B EFAULT
.I list
has an invalid address.
.TP
.B EPERM
For
.BR setgroups ,
the user is not the super-user.
.TP
.B EINVAL
For
.BR setgroups ,
.I size
is greater than
.B NGROUPS
(32 for Linux 2.0.32).
For
.BR getgroups ,
.I size
is less than the number of supplementary group IDs, but is not zero.
.SH "CONFORMING TO"
SVr4, SVID (issue 4 only; these calls were not present in SVr3),
X/OPEN, 4.3BSD. The
.B getgroups
function is in POSIX.1. Since
.B setgroups
requires privilege, it is not covered by POSIX.1.
.SH BUGS
The
.B _BSD_SOURCE
flag probably shouldn't be required for
.BR setgroups .
.SH "SEE ALSO"
.BR initgroups (3),
.BR getgid (2),
.BR setgid (2)
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