I think that advice is just outdated. It's a different situation now that it's a standard practice and there are optimizations supporting it (http://gcc.gnu.org

I think that advice is just outdated. It's a different situation now that it's a standard practice and there are optimizations supporting it (http://gcc.gnu.org/onlinedocs/gcc-2.95.3/cpp%5F1.html#SEC8 http://gcc.gnu.org/onlinedocs/gcc-2.95.3/cpp%5F1.html#SEC8).