Thanks Martin, that's just what I'll do.
However, isn't the entire point of a groveler to build a little C program that gathers information like this for later use? If one were to write a general purpose way to do this, wouldn't the logical place to put that code be in cffi-groveler? Is the main hurdle here the fact that HUGE_VAL doesn't necessarily have a representation as a Lisp interger or double-float, the only two types that cvar allows? Even though some of these sound a bit rhetorical, these are honest questions.
Zach
On Fri, Apr 26, 2013 at 8:25 AM, Martin Simmons martin@lispworks.comwrote:
On Thu, 25 Apr 2013 20:55:38 -0600, Zach said:
(constant (+huge-val+ "HUGE_VAL") :type integer)
then
(with-foreign-object (huge-ptr :uint64) (setf (mem-ref huge-ptr :uint64) +huge-val+) (nlopt-set-lower-bound opts huge-ptr))
I have also been thinking along these lines. The only thing I worry
about
is whether this is strictly correct or just correct in practice. Is
there
a guarantee that a double float is always the same size as a uint64.
It's
true on every platform I have ever programmed for (I think), but will it always be true? Back when I programmed in C more often, hard coding data type sizes into a program just seemed wrong so I didn't do it, so I
guess I
wouldn't know. Perhaps I am sweating a non-issue...
That's not the only problem -- on some platforms, HUGE_VAL is not a compile-time constant. It looks like the only portable way to get the value is to write a C helper function to return it.
-- Martin Simmons LispWorks Ltd http://www.lispworks.com/