f z wrote: > Andrew, > > I compile the release version of the test code with VC 6.0 and run it on windows xp sp2 , > but it took the same time in every try_throw_catch block ,so perhaps we can do something to improve the preformance VC uses a very different technique. DWARF exception handling, as used in GNU/Linux systems, has essentially zero overhead as long as an exception isn't thrown. However, this does mean that in the rare case when an exception is thrown, there is some searching to do. On balance this is a good compromise, as long as throwing an exception really is rare. Andrew.