diff --git a/cmd/npc/sdk.go b/cmd/npc/sdk.go
index 0fc2b5b..b8cc38f 100644
--- a/cmd/npc/sdk.go
+++ b/cmd/npc/sdk.go
@@ -31,7 +31,9 @@ func GetClientStatus() int {
 
 //export CloseClient
 func CloseClient() {
-	cl.Close()
+	if cl != nil {
+		cl.Close()
+	}
 }
 
 //export Version