Difference between std::pair and std::tuple with only two members?

There are some differences:

1. std::tuple is not required by the standard to ever be standard-layout. Every std::pair<T, Y> is standard-layout if both T and Y are standard-layout.

2. It’s a bit easier to get the contents of a pair than a tuple. You have to use a function call in the tuple case, while the pair case is just a member field.

But that’s about it.