on Sat Oct 15 2011, Nathan Ridge <zeratul976-AT-hotmail.com> wrote:
After reading this thread again, it seems to me that the reason we can't reach an agreement is that different people are proposing two fundamentally different ways of using static_vector:
1) As a variant of [std|boost]::array where not all the elements are constructed/used at the same time, and which keeps track of how many elements are currently in use.
2) As a variant of std::vector which keeps its memory on the stack, and which is used, literally, as a drop-in replacement for std::vector, in the sense that the developer was using std::vector, but then identified that in non-exceptional situations the actual number of elements used is below a certain threshold, and the program could use the optimization of not allocating memory dynamically.
It's clear to me that for use (1), exceeding the bound of the static_vector is a logic error and therefore should be undefined behaviour, whereas for (2), exceeding the bound of the static_vector is not a logic error and therefore throwing an exception is reasonable.
My own previous arguments for not throwing were based on the assumption that the use case is (1), without giving (2) much thought.
But isn't use-case 2 much better served by a vector that degrades gracefully by falling back to using the heap? I just can't see how throwing serves anyone's purpose well. -- Dave Abrahams BoostPro Computing http://www.boostpro.com