Merge pull request #3121 from ylz0923/patch-4

[fixbug] [lts-v3.1.x] [rt-thread] [components] [net] [at] [at_socket] at_socket.c

components/net/at/at_socket/at_socket.c

@@ -855,7 +855,7 @@ int at_recv(int s, void *mem, size_t len, int flags)
 int at_sendto(int socket, const void *data, size_t size, int flags, const struct sockaddr *to, socklen_t tolen)
 {
     struct at_socket *sock = RT_NULL;
-    int len, result = 0;
+    int len = 0, result = 0;
 
     if (data == RT_NULL || size == 0)
     {