diff --git a/utils.c b/utils.c
index d99ac48..ec3f195 100644
--- a/utils.c
+++ b/utils.c
@@ -264,10 +264,16 @@ int xc_undo_fix_opcode(zend_op_array *op_array TSRMLS_DC) /* {{{ */
 /* }}} */
 #endif
 
-void xc_install_function(char *filename, zend_function *func, zend_uchar type, char *key, uint len TSRMLS_DC) /* {{{ */
+void xc_install_function(char *filename, zend_function *func, zend_uchar type, void *key, uint len TSRMLS_DC) /* {{{ */
 {
 	if (func->type == ZEND_USER_FUNCTION) {
-		if (zend_u_hash_add(CG(function_table), type, key, len,
+		if (*(char *) key == '\0') {
+			zend_u_hash_update(CG(function_table), type, key, len,
+						func, sizeof(zend_op_array),
+						NULL
+						);
+		}
+		else if (zend_u_hash_add(CG(function_table), type, key, len,
 					func, sizeof(zend_op_array),
 					NULL
 					) == FAILURE) {
@@ -284,7 +290,13 @@ ZESW(xc_cest_t *, void) xc_install_class(char *filename, xc_cest_t *cest, zend_u
 	zend_class_entry *cep = CestToCePtr(*cest);
 	ZESW(void *stored_ce_ptr, NOTHING);
 
-	if (zend_u_hash_add(CG(class_table), type, key, len,
+	if (*(char *) key == '\0') {
+		zend_u_hash_update(CG(class_table), type, key, len,
+					cest, sizeof(xc_cest_t),
+					ZESW(&stored_ce_ptr, NULL)
+					);
+	}
+	else if (zend_u_hash_add(CG(class_table), type, key, len,
 				cest, sizeof(xc_cest_t),
 				ZESW(&stored_ce_ptr, NULL)
 				) == FAILURE) {
diff --git a/utils.h b/utils.h
index b9ee9dd..743b89e 100644
--- a/utils.h
+++ b/utils.h
@@ -25,7 +25,7 @@ int xc_undo_fix_opcode(zend_op_array *op_array TSRMLS_DC);
 zend_uchar xc_get_fixed_opcode(zend_uchar opcode, int line);
 
 /* installer */
-void xc_install_function(char *filename, zend_function *func, zend_uchar type, char *key, uint len TSRMLS_DC);
+void xc_install_function(char *filename, zend_function *func, zend_uchar type, void *key, uint len TSRMLS_DC);
 ZESW(xc_cest_t *, void) xc_install_class(char *filename, xc_cest_t *cest, zend_uchar type, void *key, uint len TSRMLS_DC);
 
 /* sandbox */
diff --git a/xcache.h b/xcache.h
index 8e23270..3ea77cf 100644
--- a/xcache.h
+++ b/xcache.h
@@ -77,6 +77,9 @@ typedef char *zstr;
 #	define zend_u_hash_add(ht, type, arKey, nKeyLength, pData, nDataSize, pDest) \
  	   zend_hash_add(ht, arKey, nKeyLength, pData, nDataSize, pDest)
 
+#	define zend_u_hash_update(ht, type, arKey, nKeyLength, pData, nDataSize, pDest) \
+ 	   zend_hash_update(ht, arKey, nKeyLength, pData, nDataSize, pDest)
+
 #	define zend_u_hash_find(ht, type, arKey, nKeyLength, pData) \
  	   zend_hash_find(ht, arKey, nKeyLength, pData)