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POc++ callback syntax in a class
 

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  1. POc++ callback syntax in a class
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    <p>I am trying to figure out the syntax to register a callback with this 3rd party software. I think it is probably a basic question, I just am not too familiar with c++. They have a method for registering a callback function so their code can call a function in my code when an event happens. They provided a working example that registers the callback from the main file, but I want to know how to do it when working inside a class</p> <p>Their method signature:</p> <pre><code>smHTRegisterHeadPoseCallback(smEngineHandle engine_handle, void *user_data, smHTHeadPoseCallback callback_fun); </code></pre> <p>Working example from the main file:</p> <pre><code>void STDCALL receiveHeadPose(void *,smEngineHeadPoseData head_pose, smCameraVideoFrame video_frame) { ... } void main() { ... smHTRegisterHeadPoseCallback(engine_handle,0,receiveHeadPose) ... } </code></pre> <p>But I want to use this from my class</p> <p>MyClass.h</p> <pre><code>class FaceEngine { public: void STDCALL receiveFaceData(void *, smEngineFaceData face_data, smCameraVideoFrame video_frame); ... </code></pre> <p>MyClass.cpp</p> <pre><code>void FaceEngine::Start(void) { rc = smHTRegisterFaceDataCallback(hFaceAPIEngine,0,&amp;FaceEngine::receiveFaceData); ... </code></pre> <p>Results in this compiler error:</p> <pre><code>Error 1 error C2664: 'smHTRegisterFaceDataCallback' : cannot convert parameter 3 from 'void (__stdcall FaceEngine::* )(void *,smEngineFaceData,smCameraVideoFrame)' to 'smHTFaceDataCallback' d:\stuff\programming\visual studio 2008\projects\tut02_vertices\faceengine.cpp 43 Beard </code></pre> <p>If my question isn't clear please let me know how I can clarify.</p>
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    1. USWindows programmer
    1. USMr Bell
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    1. COWhat's the declaration for `smHTFaceDataCallback` look like? The error message is saying you're not calling `smHTRegisterFaceDataCallback` correctly...
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