Why is the use of tuples in C++ not more common?

Question

Why does nobody seem to use tuples in C++, either the Boost Tuple Library or the standard library for TR1? I have read a lot of C++ code, and very rarely do I see the use of tup

Answer 1

As a data-store std::tuple has the worst characteristics of both a struct and an array; all access is nth position based but one cannot iterate through a tuple using a for loop.

So if the elements in the tuple are conceptually an array, I will use an array and if the elements are not conceptually an array, a struct (which has named elements) is more maintainable. ( a.lastname is more explanatory than std::get<1>(a)).

This leaves the transformation mentioned by the OP as the only viable usecase for tuples.