cvCreateButton 656 modules/highgui/src/window.cpp CV_IMPL int cvCreateButton(const char*, void (*)(int, void*), void*, int, int) cvCreateButton 617 modules/highgui/src/window_QT.cpp CV_IMPL int cvCreateButton(const char* button_name, CvButtonCallback on_change, void* userdata, int button_type, int initial_button_state)