Question

A simple question but I am not sure what it is done in C++.

When I have a class that have _bstr_t member.
I would like to know if does member are freed when the object is deleted:

class A {
    _bstr_t foo("Testing");
}

The A class does not have a dtor. So is the default dtor calling the dtor of yeach member of the class A?

Especially for _bstr_t because it allocate a string via SysAllocString.

Thanks

Answer 1

Yes, _bstr_t destructor will have been called – the compiler will take care of that. Even though it doesn’t have a user-defined destructor the compiler will emit code that destroys all fully constructed subobjects by calling their destructors.

Since _bstr_t has a non-trivial destructor that takes care of calling SysFreeString() that destructor will be called and release the BSTR.