为什么cpp编译器在类型声明不正确时要转换为int?

为什么编译器不告诉我它无法解析类型?

它告诉你第一个错误,我得到:

<source>:10:26: error: 'std' is not a type
   10 |     void message_handler(std:string &recieved_msg); // <- here is ":" missing
      |                          ^~~
<source>:10:29: error: expected ',' or '...' before ':' token
   10 |     void message_handler(std:string &recieved_msg); // <- here is ":" missing
      |                             ^
<source>: In member function 'void WebsocketClient::ws_data_receive_handler(esp_websocket_event_data_t*)':
<source>:15:31: error: cannot convert 'std::string' {aka 'std::__cxx11::basic_string<char>'} to 'int'
   15 |         this->message_handler(msg_recieved); // <- here it gives the error: "error: cannot convert 'std::string' {aka 'std::__cxx11::basic_string<char>'} to 'int'"
      |                               ^~~~~~~~~~~~
      |                               |
      |                               std::string {aka std::__cxx11::basic_string<char>}
<source>:10:26: note:   initializing argument 1 of 'void WebsocketClient::message_handler(int)'
   10 |     void message_handler(std:string &recieved_msg); // <- here is ":" missing
      |                          ^~~

Demo

为了诊断多个错误,编译器必须从之前的错误中“恢复”。用int/ovoid替换未知/格式错误的类型可能是一种方法。不过,这可能会导致“错误”地报告未来的错误。

所以你必须检查第一个错误才能得到准确的报告。