Seth LaForge wrote:
In this day and age, running our C++ programs off fossil fuels makes a dangerous contribution to global warming and requires purchase of carbon offsets for ethical programming. Thus I think it's time for a Boost atomic power library. Oops, sorrry, wrong meaning of atomic.
What would people think of an atomic integer library, along the lines of Linux's asm/atomic.h? I'd propose a class atomic<T> implementing operations like atomic read (implicit conversion to T), atomic set (assignment from T), and compare-and-exchange. For integral types it would support atomic add and return result (operator+=), atomic subtract and return result (operator-=), atomic increment and return result (prefix operator++), and atomic decrement and return result (prefix operator--).
For arbitrary architectures or unhandled types of T, there would be a naive implementation using a mutex. On supported architectures there would be specializations for integral T types, using assembly to implement more efficient atomic operations. This assembly could pretty much just be borrowed from the Linux asm/atomic.h headers.
What do people think? I see pros: + Cross-platform efficient atomic operations for efficient threaded apps. I see cons: - Hard to predict whether your atomic ops will be efficient (no specialization for your architecture/T). - Some architectures may implement different atomic ops, making the above ops not the most efficient.
I think the pros outweight the cons. I'd personally much rather use a Boost.atomic library than asm/atomic.h.
Seth _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost
Intel's TBB has an atomic<T> http://www.threadingbuildingblocks.org/file.php?fid=77