Example 20.6. Declare, implement, and register the callback function of SFBCamera class.

SFMTYPEDEFCLASS(Camera)
class Camera {
SFMSEALCOPY(Camera)

private:
    SFBCameraSmp _camera;      // ICamera Interface Wrapper class 

public:
    SFCError Resume(Void);                      // resume processing
    friend Void OnCameraSHP(VoidPtr reference, AEECameraNotify* notify);    // dummy callback function 
    Void OnCamera(AEECameraNotify* notify);     // actual callback function
};

#endif

// resume processing: basic initialization for camera
SFCError Camera::Resume(Void)
{
    SFCError error(SFERR_NO_ERROR);
 
    // get camera interface
    if ((_camera = SFBCamera::NewInstance()) != null) {     
    
        // register dummy callback function
        error = _camera->RegisterNotify(OnCameraSHP, this); 
        
        if (error == SFERR_NO_ERROR) {

            ...

        }
        
    // when camera interface cannot be obtained
    } else {
    
        error = SFERR_NO_MEMORY;   
    }
    
    if (error != SFERR_NO_ERROR) {
       // error processing
    }
    return error;
}

// dummy callback function 
Void OnCameraSHP(VoidPtr reference, AEECameraNotify *notify)
{
    // call actual callback function
    static_case<CameraPtr>(reference)->OnCamera(notify); 
    return;
}

// actual callback function
Void Camera::OnCamera(AEECameraNotify* notify)
{
    switch (notify->nStatus) {
        case CAM_STATUS_START:  // when camera is started
            ...
            break;
        case CAM_STATUS_FRAME:  // when new frame is obtained
            ...
            break;
        case CAM_STATUS_DONE:   // when processing is finished
            ...
            break;
        case CAM_STATUS_FAIL:   // when processing is failed
            ...
            break;
        case CAM_STATUS_ABORT:  // when processing is stopped
            ...
            break;
    }
    return;
}