mpf_t and return values

[Aram Khalili]

Hello,

I just downloaded and installed libgmp.  I need to calculate factorials
for fairly large number (up to 1000! maybe).  I'm using Stirling's
approximation for that, and a regular C double gives up at 171! .  Does
the mpf_t extend the exponent range of a double?

Also, I have a few functions that I would like to return mpf_t's.  I get
casting warnings about that.  I would also like to be able to use the
function return value as an argument to another mpf_ function, but I get
an error and warnings about that.  Is it possible?  If not, do I need to
put everything into one function?  Isn't mpf_t a pointer?  Why isn't it
treated as such?

Thanks.

-aram