diff --git a/c_wrapper/constant.go b/c_wrapper/constant.go
index cdb4e68..1798166 100644
--- a/c_wrapper/constant.go
+++ b/c_wrapper/constant.go
@@ -18,9 +18,7 @@ const (
 	CONNECT_FAILED
 	KICKED_OFFLINE
 	USER_TOKEN_EXPIRED
-)
-const (
-	JOINED_GROUP_ADDED = iota
+	JOINED_GROUP_ADDED 
 	JOINED_GROUP_DELETED
 	GROUP_MEMBER_ADDED
 	GROUP_MEMBER_DELETED
@@ -31,9 +29,7 @@ const (
 	GROUP_MEMBER_INFO_CHANGED
 	GROUP_APPLICATION_ACCEPTED
 	GROUP_APPLICATION_REJECTED
-)
-const (
-	FRIEND_APPLICATION_ADDED = iota
+	FRIEND_APPLICATION_ADDED 
 	FRIEND_APPLICATION_DELETED
 	FRIEND_APPLICATION_ACCEPTED
 	FRIEND_APPLICATION_REJECTED
@@ -42,20 +38,14 @@ const (
 	FRIEND_INFO_CHANGED
 	BLACK_ADDED
 	BLACK_DELETED
-)
-
-const (
-	SYNC_SERVER_START = iota
+	SYNC_SERVER_START 
 	SYNC_SERVER_FINISH
 	SYNC_SERVER_PROGRESS
 	SYNC_SERVER_FAILED
 	NEW_CONVERSATION
 	CONVERSATION_CHANGED
 	TOTAL_UNREAD_MESSAGE_COUNT_CHANGED
-)
-
-const (
-	RECV_NEW_MESSAGE = iota
+	RECV_NEW_MESSAGE 
 	RECV_C2C_READ_RECEIPT
 	RECV_GROUP_READ_RECEIPT
 	NEW_RECV_MESSAGE_REVOKED
@@ -64,24 +54,19 @@ const (
 	RECV_MESSAGE_EXTENSIONS_ADDED
 	RECV_OFFLINE_NEW_MESSAGE
 	MSG_DELETED
-)
-const (
-	RECV_NEW_MESSAGES = iota
+
+	RECV_NEW_MESSAGES 
 	RECV_OFFLINE_NEW_MESSAGES
-)
-const (
-	SELF_INFO_UPDATED = iota
+
+	SELF_INFO_UPDATED 
 	USER_STATUS_CHANGED
-)
-const (
-	RECV_CUSTOM_BUSINESS_MESSAGE = iota
-)
-const (
-	MESSAGE_KV_INFO_CHANGED = iota
-)
 
-const (
-	UPLOAD_FILE_CALLBACK_OPEN = iota
+	RECV_CUSTOM_BUSINESS_MESSAGE
+
+
+	MESSAGE_KV_INFO_CHANGED
+
+	UPLOAD_FILE_CALLBACK_OPEN
 	UPLOAD_FILE_CALLBACK_PART_SIZE
 	UPLOAD_FILE_CALLBACK_HASH_PART_PROGRESS
 	UPLOAD_FILE_CALLBACK_HASH_PART_COMPLETE