[Boost-users] [enable_if] Why any other than lazy?

Boost.EnableIf defines enable_if etc, and goes on to define lazy_enable_if, which the documentation states is for the circumstances and compilers when the non-lazy version would break since the instantiation for which SFINAE should apply is a nested instantiation which is not properly processed by some compilers. What I don't understand is why anyone would wish to use the non-lazy versions, since AFAICS the lazy version will always work. Then the obvious question is why the non-lazy versions exist at all? Thanks, Rob. -- ACCU - Professionalism in programming - http://www.accu.org