How to use smart pointer in this situation

Question

I want to use smart pointer in the following situation:

   SOME_STRUCT* ptr = new SOME_STRUCT;
   ptr->SOME_MEMBER = new BYTE[100];
   CallSomeAPI(ptr);

now the API can either return error or pass successfully but in both those cases i want to delete the object , one way can be to write delete statement during error exit and during normal exit.

But how can i use a smart pointer for these pointers ? By smart pointers i mean unique_ptr, shared_ptr , etc. whichever can work !

Thanks!

Answer 1

You can write a custom deleter for unique_ptr.

struct my_deleter {
    void operator()(SOME_STURCT* ptr) const {
        delete[] ptr->SOME_MEMBER;
        delete ptr;
    }
};

using my_ptr = std::unique_ptr<SOME_STRUCT, my_deleter>;

and I would suggest changing new SOME_STRUCT; to new SOME_STRUCT{}; to default initialize SOME_MEMBER to nullptr.

I am not 100% happy with this solution, so perhaps look into scope_guard or writing a wrapper class for your struct.