我是否只能通过其他类成员函数访问成员函数？

Question

As far as my knowledge goes, a friend function will give the function free access to the entire class. Can I scope this friend function by only letting it access a single member function?

For example:

class ResourceCache {
    Resource* Create(ResourceDesc) {
        ...
        return ResourceDesc.Create();
    }
}

class ResourceDesc {
    ...
    Resource* Create();
}

In this example, I want ResourceCache::Create to only have access to ResourceDesc::Create , but not to all of ResourceDesc .

Is that possible?

Answer 1

C++ doesn't give you access control this fine-grained. Don't worry too much about getting the access control precisely right, it's all code you or your collaborators have written anyway, what bad thing are you afraid might happen?

Answer 2

C++ doesn't allow that.

My immediate thought would be that if you want to do this, it's at least a possible indication that your ResourceDesc (and possibly ResourceCache as well) may be on the large side and may do more than one class really should.