CODEWITHSUNDEEP
c++classpointersconstants
bugrishka
bugrishka

Reputation: 1

How to initialise struct with constant members with certain address?

I am trying to initialise class object (which has constant members) with certain values and certain address. I understand that this is because members are constant but I need them to be constant. I tried to find solution but with no success.

So the question is: is there some "easy" way to do it?

class ints{
    public:
        const int a;
        const int b;
        ints(int a, int b);
    };

ints::ints(int a, int b) :
    a{a},
    b{b}
{}

int main() {
    auto ptr = (ints*)malloc(sizeof(ints));
    ints values{1, 2};
 // all wrong
//    *ptr = ints copy{values}; 
//    &values = ptr;
//    *ptr = values;
    std::cout << ptr->a; //ptr->a should be equal to 1
}

Upvotes: 0

Views: 68

Answers (1)

eerorika
eerorika

Reputation: 238351

You can create an object at a specific address using placement-new:

extern void* some_address;

int main()
{
    ints* ptr = new(some_address) ints{1, 2};
    std::cout << ptr->a;
}

Upvotes: 1

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