You may define your own
delete operator or deallocation
function as a class member function or a global namespace function with the
following restrictions:
- The first parameter must be of type void*.
- The return type must be of type void.
- Your deallocation function may be a template function. Neither the first
parameter nor the return type may depend on a template parameter.
The following example defines replacement functions for global namespace
new and
delete:
#include <cstdio>
#include <cstdlib>
using namespace std;
void* operator new(size_t sz) {
printf("operator new with %d bytes\n", sz);
void* p = malloc(sz);
if (p == 0) printf("Memory error\n");
return p;
}
void operator delete(void* p) {
if (p == 0) printf ("Deleting a null pointer\n");
else {
printf("delete object\n");
free(p);
}
}
struct A {
const char* data;
A() : data("Text String") { printf("Constructor of S\n"); }
~A() { printf("Destructor of S\n"); }
};
int main() {
A* ap1 = new A;
delete ap1;
printf("Array of size 2:\n");
A* ap2 = new A[2];
delete[] ap2;
}
The following is the output of the above example:
operator
new with 40 bytes
operator new with 33 bytes
operator new with 4 bytes
Constructor of S
Destructor of S
delete object
Array of size 2:
operator new with 16 bytes
Constructor of S
Constructor of S
Destructor of S
Destructor of S
delete object