The std::enable_shared_from_this class is a (template) mixin, recommended for use to enable creating shared pointers from a given object (or its address), which all have common ownership of the object.
The thing is, that if you have an class T which:
- Has virtual methods
- inherits from
std::enable_shared_from_this<T>(and the inheritance must be public as detailed at the link above; otherwise the mixin is useless) - Gets compiled with GCC with
-Wnon-virtual-dtor(perhaps also with clang, I'm not sure)
you get warnings about the non-virtual destructor of std::enable_shared_from_this.
My question is - where is the fault here? That is...
- Should
std::enable_shared_from_thishave a virtual destructor? (I don't think so) - Should the non-virtual-destructor warning employ some criterion for when it is emitted (if at all enabled, that is)?
- Should the destructor of
std::enable_shared_from_thisbe made protected? (And will this even work?) - Should classes with this mixin not have virtual methods at all?
I'm confused.
There is no fault; your code is fine. It's merely a false-positive. The point of a warning is to detect pieces of code which, although valid C++, usually indicate problems. But "usually" does not mean "always", so most warnings have cases of false-positives, where it thinks there is misuse when there actually is not.
No code is expected to delete a pointer to
enable_shared_from_this. So no.It's not reasonable for a compiler to know everything about what you're intending to do. It's just seeing something that's usually a problem, which you've decided to have it flag. In this case, it's not a problem.
No.
No.