#include <iostream>
#include <memory.h>
using namespace std;

void modify(void*& __ptr)
 {
    char* temp = new char[50];
    strcpy(temp,"testing");
    __ptr=(void*)temp;
    std::cout<<"__ptr="<<(char*)__ptr<<endl;
 }

 int main()
 {
    char* str;
    modify(str);
    std::cout<<"str="<<str;
    return 0;
 }