CODEWITHSUNDEEP
c++freearmadillo
Haj Nasser
Haj Nasser

Reputation: 304

Free memory in c++ (armadillo)

I want to free memory after using an object ('ii', in the following program) in c++:

#include <iostream>
#include <armadillo>

using namespace std;
using namespace arma;

int main()
{
    cx_mat ii(2,2,fill::eye);
    cout << ii <<endl;
    free (ii);
    return 0;
}

But after compiling, I encounter to the following error:

error: cannot convert ‘arma::cx_mat {aka arma::Mat<std::complex<double> >}’ to ‘void*’ for argument ‘1’ to ‘void free(void*)’

can any body guide me?

Upvotes: 0

Views: 1552

Answers (3)

user2684182
user2684182

Reputation:

The reason you're getting the error you're getting is because you're not passing a pointer to the function.

However, free requires that you pass a pointer that has been returned by malloc, calloc, or realloc, otherwise undefined behavior occurs.

The memory of your object will be freed when your function returns, or exits.

Upvotes: 1

Maresh
Maresh

Reputation: 4712

cx_mat ii(2,2,fill::eye);

That's allocated on the stack, you can't free it, it will be destroyed when your program exits the scope.

http://gribblelab.org/CBootcamp/7_Memory_Stack_vs_Heap.html

Upvotes: 2

Baum mit Augen
Baum mit Augen

Reputation: 50053

You can only free pointers holding an address returned by malloc, calloc or realloc. Nothing else. In particular, no matrices.

You also should not need to use free in C++, ever.

In your case, you do not need to do anything to free the memory, the destructor of the matrix will take care of that.

Upvotes: 1

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