Register a callback that will be invoked prior to entering the execution loop.
#include <glview/glview.h>
GLVIEW_API int glview_register_initialize_callback(initialize_callback initialize_callback)
The function to call prior to glview_loop() entering the execution loop. If initialize_callback is NULL, any previously registered callback will be disabled and no function will be called prior to entering the execution loop.
GLVIEW_SUCCESS