That's part of whatever windowing toolkit you are using, not OpenGL itself.
Vsync!! That's exactly what I want to check. How would I be able to check the status of Vsync?Yes, pretty much.
Also, if Vsync is ON, how would I be able to make my fps as fast as 120Hz? Do I just need to keep the elapsed time of each of my frame to be less that 1second/120?
Thanks a lot for the reply. It's helpful, but not 100% solve my problem. Could you give me more hints about the details of the windowing toolkit part. For example, I tried SDL, but it doesn't seem to support what I want to do. Do you know anything that does and could you give me some detailed examples?