C++ portability guide
I was looking for this document a while ago and couldn't seem to find it but I stumbled across it moments ago almost by chance. It's the the Mozilla guidance for C++ portability - give it a read here if you are interested in that stuff it is full of subtle pointers that make sense (and some that are not that obvious).
If you have a spare few minutes give it a read, it is fairly comprehensive but at the same time I would take some of it with a pinch of salt.