[Boost-users] dubious range mismatch prerequisite

The documentation for mismatch, as applied to ranges, says that rng2 must be at least as long as rng1. Why is this precondition necessary? The precondition is impossible to evaluate for bare input iterators without destroying the iterators, whereupon it is impossible to call mismatch any more. IMHO, it would be perfectly reasonable to stop at the end of rng2 if rng2 is shorter. <URL: http://www.boost.org/doc/libs/1_47_0/libs/range/ doc/html/range/reference/algorithms/non_mutating/mismatch.html >