How to do an atomic increment and fetch in C?

Question

I'm looking for a way to atomically increment a short, and then return that value. I need to do this both in kernel mode and in user mode, so it's in C, under Linux, on Intel 32bit architecture. Unfortunately, due to speed requirements, a mutex lock isn't going to be a good option.

Is there any other way to do this? At this point, it seems like the only option available is to inline some assembly. If that's the case, could someone point me towards the appropriate instructions?

Answer 1

GCC supports atomic operations:

gcc atomics