According to the v0.5 docs, `ccall(..., (Ptr{BigFloat},..), &aBigFloat,
..)` is deprecated in favor of `ccall(..., (Ref{BigFloat},..), aBigFloat,
..)`.
It seems that using `Ptr{Type}` needs to be paired with `&varOfType` using
the ampersand. When would one use `Ptr{Type}`?- [julia-users] in ccall when to use Ptr{} rather than Ref{}... Jeffrey Sarnoff
