+passing the address of the structure to fill in; this overwrites the
+previous contents of the
+.BR cp_uid ,
+.BR cp_gid ,
+and
+.BR cp_gids
+members. Alternatively, the functions
+.BR checkpath_setuid ,
+.BR checkpath_setgid ,
+and
+.B checkpath_setgroups
+can be called to do the job in stages. The
+.B checkpath_setuid
+function simply stores the process's real uid in
+.BR cp_uid .
+The
+.B checkpath_setgid
+and
+.B checkpath_setgroups
+functions store respectively the process's real gid and supplementary
+gids in the
+.B cp_gid
+array; they avoid inserting duplicate entries; they return 0 on success
+or \-1 if the table would overflow; they assume that the table is
+properly set up (minimally, just set
+.BR "cp_gids = 0" ).
+They use a utility function
+.B checkpath_addgid
+to do their work; it takes a pointer to a
+.B struct checkpath
+and a gid, and again returns 0 on success or \-1 if overflow would
+occur.