CODEWITHSUNDEEP
c++
santosh kumar
santosh kumar

Reputation: 585

How to free dynamic memory if exception occurs in constructor?

I came across a situation where constructor allocated the dynamic memory and if any exception occurs in the constructor, it was not freeing the dynamically allocated memory. To avoid such situation I used unique_ptr, and it is able to free the memory properly.

To showcase the situation here is a dummy code for that.

class ExceptionInConstructor
{
 unique_ptr<int> a;
public:
    ExceptionInConstructor()
    {
        a = std::unique_ptr<int>( new int(10));
        cout <<"Constructor called. Value of a is "<< *a<<endl;
        //some exception occurs after the mrmory allocation
        throw exception();
    }
    ~ExceptionInConstructor()
    {
        cout << "Dest called()"<<endl;
    }
};

int main()
{ 
    try
    {       
        ExceptionInConstructor ex; 
    }
    catch(...)
    {}  
    return 0;
 }

Is it a correct and efficient way for such a situation or is there any better option for such a scenario?

Edit 1: Removed the commented code in destructor which was left by mistake

Upvotes: 1

Views: 207

Answers (1)

Stephan Dollberg
Stephan Dollberg

Reputation: 34618

No, that is exactly the point and intended use case for smart pointers and RAII in general.

Also note that your delete a in your destructor is wrong in any case as the unique_ptr is not a pointer itself. Relatedly, destructors are also not called if there is an exception in the constructor.

Upvotes: 1

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