Trailing u in Hex Number C/C++

Question

Possible Duplicate:
Meaning of U suffix

I'm going through code that has a bunch of defines that look like: #define HEX_NUMBER (0x000000FFu)

What is the trailing u? I've tried compiling with and without it and I don't see any difference.

Solution

Appending u to any integral constant makes the compiler interpret it as unsigned.

Comments

[Kerrek SB]

"interpret" is a bit misleading. What's happening is that the type of the literal expression is an unsigned type.