#include <sys/types.h>
     #include <unistd.h>

     int
     getgroups(int gidsetlen, gid_t *gidset);

DESCRIPTION

     Getgroups() gets the current group access list of the current user
     process and stores it in the array gidset.  The parameter gidsetlen indi-
     cates the number of entries that may be placed in gidset.  Getgroups()
     returns the actual number of groups returned in gidset.  No more than
     {NGROUPS_MAX} will ever be returned.  If gidsetlen is 0, getgroups()
     returns the number of groups without modifying the gidset array.

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.

SEE ALSO

     setgroups(2), initgroups(3)

HISTORY

     The getgroups() function call appeared in 4.2BSD.

4.2 Berkeley Distribution       April 16, 1994       4.2 Berkeley Distribution