Cython: Assign pointer values, not the pointer itself

Question

C/C++ allows assigning values of a pointer to another pointer of the same type:

#include <iostream>

using namespace std;

int main() {
    int* a = new int();
    int* b = new int();

    *a = 999;
    *b = *a; // Can't do in Cython this?

    cout <<"Different pointers, same value:" <<endl;
    cout <<a <<" " <<b <<endl;
    cout <<*a <<" " <<*b <<endl;
} 

Is it possible to write the line *b = *a above in Cython?

All these fail:

from cython.operator cimport dereference as deref

cdef cppclass foo: # Can't `new int()` in Cython, make a class
    int value 

cdef foo* a = new foo()
cdef foo* b = new foo()

a.value = 999
deref(b) = deref(a) # Error: Cannot assign to or delete this
b        = deref(a) # Error: Cannot assign type 'foo' to 'foo *'
deref(b) = a        # Error: Cannot assign to or delete this
b        = a        # Works, but pointer 'b' is gone!!! not a clone.

Answer 1

Using b[0] = a[0] seems to do the trick. Indexing is another way to dereference the pointer. Here's some example code and its output.

# distutils: language=c++


cdef cppclass foo:
    int value 

cdef foo* a = new foo()
cdef foo* b = new foo()

a.value = 999
b.value = 777

print('initial values', a.value, b.value)
print('initial pointers', <long>a, <long>b)

b[0] = a[0]

print('final pointers', <long>a, <long>b)
print('final values', a.value, b.value)

As you can see, the values of b have changed, but the pointer still references the same address as before.

initial values 999 777
initial pointers 105553136305600 105553136304304
final pointers 105553136305600 105553136304304
final values 999 999