on 03.05.2010 at 15:39 Stewart, Robert wrote :
Chad Nelson wrote:
If I read your example correctly, then that's about what I was thinking of: algorithms that have to start with a copy of one or more of the passed-in parameters, but then need to modify it/them. The division algorithm requires this, just as one example off the top of my head.
If your algorithm requires a copy, then COW should make it slower because it will first manipulate the reference count and because you must query in each mutating operation whether to make a unique copy.
i believe that mutating operations are so expensive that the cow overhead becomes negligible and one can live with it unless he is very pedantic and yes, i think that cow is pretty useful here especially complemented by "rvalue&move awareness" also one should take into account that implicit sharing (cow) can be made thread safe with little effort from the author (just a couple of atomic ops) i.e. as soon as atomic lib becomes a part of boost cow implementation of xint can be made thread safe by your (lib user) desire i'm glad that everyone switched to the implementation because it means there is nothing criminally wrong with the interface said that, we can expect the implementation to become optimal in time so the main work is done i guess congratulations! -- Pavel P.S. if you notice a grammar mistake or weird phrasing in my message please point it out