How can I fix the argument type conversion compiler errors in this method using a lambda function?-CodePudding

I am programming for the ESP32 (a sort of Arduino like chip). However, to easier/faster find compiler errors/warnings and later make a sort of virtualization on the PC, I like to compile the code also on a PC (using Visual Studio).

However, I cannot get the following code to compile on a PC (while it compiles in the Arduino IDE for ESP32):

server.on("/", HTTP_GET, [](AsyncWebServerRequest* request)
    {
        request->send_P(200, "text/html", textBuffer, Processor);
    });

The errors I get are:

Severity    Code    Description Project File    Line    Suppression State
Error (active)  E0413   no suitable conversion function from "lambda []void (AsyncWebServerRequest *request)->void" to "AsyncWebServerRequest *" exists RelayBox    C:\Users\miche\source\repos\RelayBox2\RelayBox\RelayBox\RelayBoxServer.cpp  203 
Error   C2664   'void AsyncWebServer::on(const char *,int,AsyncWebServerRequest *)': cannot convert argument 3 from 'RelayBoxServer::Send::<lambda_6ffcff35888ca3a1f1d7d541e1edeba3>' to 'AsyncWebServerRequest *'  RelayBox    C:\Users\miche\source\repos\RelayBox2\RelayBox\RelayBox\RelayBoxServer.cpp  206

The code is based on the ESP32 library at https://github.com/me-no-dev/ESPAsyncWebServer/blob/master/src/ESPAsyncWebServer.h

And the 'stub' classes I created using library above but simplified for my project, with '...' as irrelevant code:

class AsyncWebServer
{
    ...
    void on(const char* something, int httpGet, AsyncWebServerRequest* function);
    ...
}

#define HTTP_GET           100

class AsyncWebServerRequest
{
public:
    void send_P(int port, const char* textHmlt, STRING text, ProcessorHandlerFunction function);
};

class ArduinoStringStub : public std::string
{
   ...
}

How can I fix the argument type conversion compiler errors in this method using a lambda function?

CodePudding user response：

I've checked your reference github, it seems that the origin AsyncWebServer class has such signature:

AsyncCallbackWebHandler& on(const char* uri, WebRequestMethodComposite method, ArRequestHandlerFunction onRequest);

And ArRequestHandlerFunction is actually:

typedef std::function<void(AsyncWebServerRequest *request)> ArRequestHandlerFunction;

So it seems to be that the stub/mock AsyncWebServer you create should not take AsyncWebServerRequest* but ArRequestHandlerFunction as the on method's last parameter, corresponding with the original code.