If I have a vector of pairs:

std::vector<:pair int> > vec;

Is there and easy way to sort the list in increasing order based on the second element of the pair?

I know I can write a little function object that will do the work, but is there a way to use existing parts of the STL and std::less to do the work directly?

EDIT: I understand that I can write a separate function or class to pass to the third argument to sort. The question is whether or not I can build it out of standard stuff. I'd really something that looks like:

std::sort(vec.begin(), vec.end(), std::something_magic());