Added check for NULL message

main.c

@@ -108,6 +108,12 @@ int main() {
 					}
 
 					char* message = fetch_message_string(data);
+					if (message == NULL) {
+						printf("Invalid message.\n");
+						return -10;
+					}	
+
+					printf("Your message is: %s\n",message);
 
 					close(conn_sockets[i]);