Set the callback data that will be passed into callback functions.
#include <glview/glview.h>
GLVIEW_API int glview_set_callback_data(void *callback_data)
Application-specific data that will be passed as a parameter to each of the registered callbacks whenever they are fired. This can be changed by calling glview_set_callback_data() again. This can be set to NULL, in which case any previously set callback_data will no longer be passed into a callback.
Calling this function with a NULL parameter will result in a NULL being passed into any registered callback when invoked by glview.
GLVIEW_SUCCESS