Howard Hinnant wrote: [...]
Somehow I think I knew this and had just completely forgotten about it (I actually already had your proof of concept implementation bookmarked). Thanks for the reminder!
You're also doing PPC, right? WinXX's InterlockedIncrement, InterlockedDecrement, and InterlockedCompareExchange are fully fenced (bidirectional "full stop" barrier for loads and stores imposed on both compiler and hardware). You can do better than that. http://google.com/groups?selm=3F17EF6F.97295E7D%40web.de decrement() shall have the effect of release memory sync operation if the resulting value of a reference count is not zero; otherwise, this function shall have the effect of acquire memory synchronization operation. For compiler that still means "full stop" but not so for hardware (or whoever does runtime reodering). increment() doesn't impose any reordering constraints. decrement(msync::acq{, ...}) shall have the effect of acquire memory sync operation if the resulting value of a reference count is zero; otherwise, the memory synchronization effect of this function is unspecified. decrement(msync::rel{, ...}) shall have the effect of release memory synchronization operation if the resulting value of a reference count is not zero; otherwise, the memory sync effect of this function is unspecified. regards, alexander.