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c++smart-pointersshared-ptrauto-ptr

C++ smart pointer for a non-object type?


I'm trying to use smart pointers such as auto_ptr, shared_ptr. However, I don't know how to use it in this situation.

CvMemStorage *storage = cvCreateMemStorage();
... use the pointer ...
cvReleaseMemStorage(&storage);

I'm not sure, but I think that the storage variable is just a malloc'ed memory, not a C++ class object. Is there a way to use the smart pointers for the storage variable?

Thank you.


Solution

  • shared_ptr allows you do specify a custom deallocator. However, looking at the documentation cvReleaseMemStorage() doesn't have the right form (void f(T*)) and you need a wrapper:

    void myCvReleaseMemStorage(CvMemStorage* p) {
       cvReleaseMemStorage(&p);
    }
    
    shared_ptr<CvMemStorage> sp(cvCreateMemStorage(), &myCvReleaseMemStorage);