DIFF_KEY         3526 ext/standard/array.c 				} else if (behavior == DIFF_KEY) { /* only when DIFF_KEY */
DIFF_KEY         3601 ext/standard/array.c 	php_array_diff(INTERNAL_FUNCTION_PARAM_PASSTHRU, DIFF_KEY, DIFF_COMP_DATA_INTERNAL, DIFF_COMP_KEY_USER);