How to perform atomic operations on Linux that work on x86, arm, GCC and icc?

Question

Every Modern OS provides today some atomic operations:

• Windows has Interlocked* API
• FreeBSD has

Answer 1

I recently did an implementation of such a thing and I was confronted to the same difficulties as you are. My solution was basically the following:

• try to detect the gcc builtins with the feature macro
• if not available just implement something like cmpxch with __asm__ for the other architectures (ARM is a bit more complicated than that). Just do that for one possible size, e.g sizeof(int).
• implement all other functionality on top of that one or two primitives with inline functions