Thread: API basics

I understand that there is:

Code:

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)

which is the main function for the window.

Then there is:

Code:

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)

which does the main processing for the window and that the WinMain function calls this function in the "DispatchMessage(&Msg);" call but how do I create a variable in the main function so that it can be accessed in the WndProc function?