When you see this line of code in your source window, how does your brain read it?
My brain says “There’s a hex number, with a couple of 1′s in it.”
Guess what? WRONG. It has one ’1′. The end character is a secret hidden lowercase “L”. Thanks, Microsoft. Lucida console has literally a one pixel difference between it’s ’1′ and ‘l’, which is fairly typical. These things are speckled all over mmsystem.h. Personally I never use ‘L’ at the end of a hex digit, and if I was feeling clinically insane enough to do it, I’d at least use a capital ‘L’.