+sets the real and effective
+user IDs and the saved set-user-ID of the current process
+to the specified value.
+The
+.Fn setuid
+function is permitted if the specified ID is equal to the real user ID
+of the process, or if the effective user ID is that of the super user.
+.Pp
+The
+.Fn setgid
+function
+sets the real and effective
+group IDs and the saved set-group-ID of the current process
+to the specified value.
+The
+.Fn setgid
+function is permitted if the specified ID is equal to the real group ID
+of the process, or if the effective user ID is that of the super user.