Re: [Boost-users] Question about traversing mpl vectors

"Stephen Gross" writes:

Let's say I've got some mpl::vector. If I grab a begin iterator on it, and increment that iterator past the elements in the vector, what happens? For instance:

================================================== using boost; typedef mpl::vector t; typedef mpl::begin<t>::type element0; // Should deref to 'int' typedef mpl::next<element0>::type element1; // Should deref to 'char' typedef mpl::next<element1>::type element2; // What happens?

Undefined behavior. If you're lucky, a compilation error.

typedef mpl::next<element2>::type element3; // " typedef mpl::next<element3>::type element4; // " ==================================================

Will boost let me iterate past the 'end' of an mpl::vector?

There are no guarantees in that regard.

Am I supposed to take care of bounds checking?

If bounds need to be checked, you're supposed to take care of it. I can't say as I've ever had to do bounds checking in MPL code, though. HTH, -- Dave Abrahams Boost Consulting www.boost-consulting.com