Function that takes an STL iterator over ANY container of a elements of a specific type

Question

How would I define a function that takes as input an iterator over any type of STL container, but only to those of a specific templated type. For example:

Any iterator o

Answer 1

In addition to the existing answers relying on SFINAE, a simpler approximation would be to simply define the function to take an arbitrary template type as the iterator:

template 
void function(Iter first, Iter last){
  Unit* val = *first;
}

This has a few downsides. Unlike the SFINAE solution (such as boost::enable_if), this doesn't give you exactly what you asked for. This compiles as long as an object of type Iter can be dereferenced yielding a value convertible to Unit*, which isn't quite the same thing. You have no guarantee that Iter is a completely STL-compliant iterator (it may just be another type which defines operator*), or that its value type is Unit* precisely.

On the other hand, it's much simpler.