Thread: unordered_set with pointers

Hi, I'm figuring out how to work with std::unordered_set.

Some sites indicate that you need to create custom hashing and comparison functions when using unordered_set with custom classes but is that the case if you only use pointers to custom classes?

This is my testing code:

Code:

std::unordered_set<MyClass*> unord;
unord.insert(&level.myClasses[0]);
unord.insert(&level.myClasses[1]);
unord.erase(&level.myClasses[0]);
Print((int)unord.size());

This works, the erase() removes an object and the size() afterwards is correct, but is this safe? Can I rely on that standard pointer/adress comparison will work?

The pointers will all point to the same class type. Since pointer comparison just compares adresses, which boils down to something like an integer comparison, I'm guessing that such comparisons are "built in" to unordered_set without the need for custom hashing and comparison functions, but I want to make sure.

I found an answer here, pointer functionality is indeed included in unordered_set:

The unordered associative containers std::unordered_set, std::unordered_multiset, std::unordered_map, std::unordered_multimap use specializations of the template std::hash as the default hash function.

Each standard library header that declares the template std::hash provides enabled specializations of std::hash for std::nullptr t and all cv-unqualified arithmetic types (including any extended integer types), all enumeration types, and all pointer types.
std::hash - cppreference.com

And in a thread about unordered_set here:

For pointers, which is what the question is about, there is a specialisation of std::hash in the standard library, so nothing to worry about.
c++ - Should I use std::set or std::unordered_set for a set of pointers? - Stack Overflow