使用unique_ptr向量的原始指针作为ID进行排序

Question

I'd love to ask if this is a good practice. Let's assume this scenario:

std::vector<unique_ptr<Model>> data;

Is it safe to work with the raw pointers from this vector (raw pointer from each unique_ptr in the vector)? I understand that the vector might reallocate the data when exceeding the reserved space but that would affect only the addresses of the unique_ptr while the inner raw pointer is guaranteed to stay the same right?

Therefore, is it safe to identify the models by using those raw pointers instead of adding some id members?

More concretely, is it OK to use those raw pointers as keys in a map? I need to sort objects which contain a model pointer (as a member) from the vector and make groups of the objects with the same models.

I know I can use some handles like indexes into the vector or unique IDs but that would be a useless overhead probably. The reason I am asking is that depending on pointer address feels somehow unsafe to me :-)

Answer 1

Yep! That's fine :)

Just make sure that the objects outlive their pointers, as usual.