.TH GETGROUPS 2
.SH NAME
getgroups, setgroups \- get or set supplementary group id's
.SH SYNOPSIS
.ft B
.nf
#include <sys/types.h>
#include <unistd.h>

int getgroups(int \fIgidsetlen\fP, gid_t *\fIgidset\fP)
int setgroups(int \fIgidsetlen\fP, gid_t *\fIgidset\fP)
.fi
.ft P
.SH DESCRIPTION
.B Getgroups()
fills the array
.I gidset
of length
.I gidsetlen
with the supplementary group id's of the current process.  It returns the
actual number of id's placed in the array.  The return value is -1 and
.B errno
is set to
.B EINVAL
if the array is not big enough for all the id's.  One may call
.B getgroups
with
.I gidsetlen
set to zero to query the number of supplementary group id's currently set
for the process.  The value of
.I gidset
is then not used.
.PP
.B Setgroups()
may be used by a process with super-user privileges to set the
supplementary group id's of the process to the
.I gidsetlen
group id's in the array
.IR gidset .
.B Setgroups
returns -1 and sets
.B errno
to
.B EINVAL
if the number of id's is larger than the maximum reported by
.BR sysconf (2).
.SH "SEE ALSO"
.BR sysconf (2),
.BR initgroups (3).
.SH AUTHOR
Kees J. Bot (kjb@cs.vu.nl)
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.\" $PchId: getgroups.2,v 1.3 1995/11/27 19:38:13 philip Exp $