video synchronization

I am conducting a timing test that writes an off screen world to the CRT. It is critical that the program does not start drawing half way through a screen. Is there a way to gain control over the video synchronization, or to at least identify the start of a refresh?

There is no generic way for this in OpenGL. There is AFAIK an extension that works in Windows that gives a hint to the driver to sync buffer flips with video refresh. Anyway most drivers has a setting for syncing with video refresh or not.