Overriding virtual function differs C++

Question

I am new to C++. I have downloaded this project and when I try to run it I get:

Severity    Code    Description Project File    Line    Suppression State
Error   C2695   'TFruityGain::Idle': overriding virtual function differs from 'TCPPFruityPlug::Idle' only by calling convention FruityGain_VC   c:source\c\fruitygain_vc\gain.h 38

C++ Class:

class TFruityGain : public TCPPFruityPlug {
    private:
    public:
    virtual void _stdcall Idle();

};

class TCPPFruityPlug : public TFruityPlug {
    // some audio properties
    TAudioRenderer AudioRenderer;

    // temp buffer
    PWAV32FM ProcessTempBuffer;
    int MaxProcessLength;

    float PitchMul;
    TFruityPlugHost *PlugHost;

    virtual void Idle();
};

Remove the `virtual void Idle();` line from `TCPPFruityPlug` entirely. That line declares a logically separate *new* virtual method. I assume you instead want to override `TFruityGain::Idle`, in which case you don't need anything in `TCPPFruityPlug`'s class definition because C++ doesn't require explicit `override` (though you should use it: https://en.cppreference.com/w/cpp/language/override ) — Dai, Dec 30 '20 at 19:02
I think you need to either add or remove `_stdcall` from one of the functions in `TFruityGain` and `TCPPFruityPlug`. — David G, Dec 30 '20 at 19:02
Please search for the error message first and in this case also the Cxxxx error code. — Ulrich Eckhardt, Dec 30 '20 at 19:19
If you are using C++11 or later, you should change `virtual void _stdcall Idle();` to `void Idle() override;` in `TFruityGain` — Remy Lebeau, Dec 30 '20 at 19:21
@UlrichEckhardt I did but I didn't understand, its a sample project, I was hoping it would come working, and if there were any issues it would be config stuff. — Dev, Dec 30 '20 at 19:23

score 3 · Accepted Answer · answered Dec 30 '20 at 19:04

differs from 'TCPPFruityPlug::Idle' only by calling convention

This issue comes from the fact that you have:

virtual void _stdcall Idle();

and

virtual void Idle();

And when you override a function you want the same calling convention, see:

What is the meaning and usage of __stdcall?

Overriding virtual function differs C++

1 Answers1