CODEWITHSUNDEEP
c++c
Sam
Sam

Reputation: 238

Is it possible to convert a pointer to contiguous memory of known size into a structure?

Ex.

int pages[3];
int *page_ptr;
page_ptr = pages;

//

test a;
*page_pointer = a;

I want to take a structure (test) of same size as pages and place it at the memory location of pages. Is this possible?

Upvotes: 0

Views: 72

Answers (1)

R Sahu
R Sahu

Reputation: 206697

I want to take a structure (test) of same size as pages and place it at the memory location of pages. Is this possible?

Yes, it is possible. However, instead of using

*page_pointer = a;

you should use memcpy.

memcpy(page_pointer, &a, sizeof(pages));

Update, in response to comment by OP

I think you are asking whether you can do something like:

#include <iostream>

struct foo
{
   int a;
   int b;
   int c;
};

int main()
{
   int array[3] = {10, 20, 30};
   foo* ptr = static_cast<foo*>((void*)array);
   std::cout << ptr->a << ", " << ptr->b << ", " << ptr->c << std::endl;
}

I tried it on g++ 4.9.2 and works OK. I am not sure whether it violates any type aliasing rules.

Upvotes: 1

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