Question about Clipping

I know that entities get clipped when they are past the clip_far range. However, how you one determine whether an entity is within the camera's arc of visibility?

For instance, it might be near enough to render, but somewhere off to the side, or behind the camera, and would not be visible...

Is there a flag or variable that is set when an entity is both within the clipping range, and withing the camera's actual arc?

Ah ... I think I found it. It is the CLIPPED eflag.

if (!(my.eflags&CLIPPED)) //if I am not clipped...