test-new-overide.cpp

#include <inttypes.h>
#include <stdlib.h>
#include <stdio.h>

//#define NEW 1

#if NEW
namespace ap {
static void *operator_new(size_t size)
{
    if (size < 1) {
        size = 1;
    }

    printf("local new operator: calloc %zd\n", size);

    return calloc(size, 1);
}

void operator_delete(void *p)
{
    free(p);
}

}

class CallocAllocator {
public:
    void *operator new(size_t sz) {
        return ap::operator_new(sz);
    }
    void *operator new[](size_t sz) {
        return ap::operator_new(sz);
    }
    void operator delete(void *p) {
        ap::operator_delete(p);
    }
    void operator delete[](void *p) {
        ap::operator_delete(p);
    }
};

#else

class CallocAllocator {
};

void * operator new(size_t size)
{
    if (size < 1) {
        size = 1;
    }
    return(calloc(size, 1));
}

void operator delete(void *p)
{
    if (p) free(p);
}

void * operator new[](size_t size)
{
    if (size < 1) {
        size = 1;
    }
    return(calloc(size, 1));
}

void operator delete[](void * ptr)
{
    if (ptr) free(ptr);
}

#endif

class A : public CallocAllocator {
public:
    A(uint32_t a) : a(a) { }
    A() { }

    uint32_t a;
};

int main(int argc, char *argv[])
{
    A *a = new A();

    if (a->a > 0) {
        printf("Whaaat??\n");
    }
    delete a;

    return 0;
}