GETGROUPS(2) MachTen Programmer’s Manual GETGROUPS(2)

NAME
getgroups - get group access list

SYNOPSIS
#include <sys/param.h>
#include <unistd.h>

int
getgroups(int gidsetlen, gid_t *gidset)

DESCRIPTION
Getgroups() gets the current group access list of the user process and
stores it in the array gidset. The parameter gidsetlen indicates the num-
ber of entries that may be placed in gidset. Getgroups() returns the ac-
tual number of groups returned in gidset. No more than NGROUPS, as de-
fined in <sys/param.h>, will ever be returned.

RETURN VALUES
A successful call returns the number of groups in the group set. A value
of -1 indicates that an error occurred, and the error code is stored in
the global variable errno.

ERRORS
The possible errors for getgroups() are:

[EINVAL] The argument gidsetlen is smaller than the number of groups
in the group set.

[EFAULT] The argument gidset specifies an invalid address.