.TH GETGROUPS 2
.UC 4
.SH NAME
getgroups, setgroups \- get/set groups
.SH SYNOPSIS
.nf
.B #include <sys/types.h>
.B #include <unistd.h>
.B int getgroups (int len, gid_t *groups); 
.B int setgroups (int len, const gid_t *groups); 
.fi
.SH DESCRIPTION
.B getgroups()
and 
.B setgroups()
get and set suplementary group ID's respecitvely.  The parameters are 
.I len,
length of the array,
and 
.I groups,
an array of 
.B gid_t's. 
.PP
.B setgroups()
returns 0 on success, a negative value on failure.
.PP
.B getgroups()
returns the number of groups on success, a negative value on
failure.
.SH ERRORS
.B -EINVAL
is returned when 
.I len
is not large enough.
.PP
.B -EPERM
is returned when a non-superuser tries to 
.B setgroups().
.PP
.SH FILES
/usr/include/linux/sys.h
.br
/usr/include/unistd.h
.SH SEE ALSO
setgid(2)
.SH BUGS
.B setgroups()
fails silently when 
.I len 
> 
.B NRGROUPS, 
which is defined as 32 in param.h.