How to get the real and total length of char * (char array)?

Question

For a char [], I can easily get its length by:

char a[] = \"aaaaa\";
int length = sizeof(a)/sizeof(char); // length=6

However,

Answer 1

You can implement your own new and delete functions, as well as an additional get-size function:

#define CEIL_DIV(x,y) (((x)-1)/(y)+1)

void* my_new(int size)
{
    if (size > 0)
    {
        int* ptr = new int[1+CEIL_DIV(size,sizeof(int))];
        if (ptr)
        {
            ptr[0] = size;
            return ptr+1;
        }
    }
    return 0;
}

void my_delete(void* mem)
{
    int* ptr = (int*)mem-1;
    delete ptr;
}

int my_size(void* mem)
{
    int* ptr = (int*)mem-1;
    return ptr[0];
}

Alternatively, you can override the new and delete operators in a similar manner.