Datetime as a time_t?

Hello,

Does anyone know how to extract a datetime field as a time_t?
My understanding is that PostgreSQL stores dates internally
as a time_t, but I have not figured out how to extract them in
that format.

I have looked at the casting, and the set datestyles so far.
Any ideas?

Thanks,

-Ryan

P.S. I am using PostgreSQL 6.5.3