convert mpf t to double with rounding-modes defined by ieee754

[Torbjorn Granlund]

usenett at gmx.de writes:

  Isn't there any good tutorial how to do such things?

There is some stuff in the manual:
  http://swox.com/gmp/manual/Float-Internals.html#Float%20Internals

But as others already have suggested, using mpfr might be the way
to go.

--
Torbjörn