C++ :: Running Unit Test On Library - Checking For NAN?

I am running a unit test on a library and this line keeps failing on Fedora 16, G++ 4.6.2

Code:
assertNAN(double, std::numeric_limits<double>::signaling_NaN()); //sanity check

The assert looks like this

Code:
//needs to copy it so that if its a function call it only does it once
#define assertNAN(type, one) {
type val = (type)one;
std::string lag(#one);
lag += " not a number";

[Code] ...

I am compiling with -DNDEBUG -O3 -ffast-math -fexpensive-optimizations to simulate a production environment. Is there a way to test for NAN consistently?