Well, there's not a lot of context to say whether there are more shared counters. That said, I overlooked the MAP_SHARED, and the code actually got itself in no

Well, there's not a lot of context to say whether there are more shared counters. That said, I overlooked the MAP_SHARED, and the code actually got itself in non-portable land. Not all atomics are actually atomics. IIRC, at least ARM doesn't have 64-bits atomics, and using atomics on such platforms means using locks. Which are very likely to not work properly in shared memory.