How to check whether all bytes in a memory block are zero

Question

I have a block of memory with elements of fixed size, say 100 bytes, put into it one after another, all with the same fixed length, so memory looks like this

&l         


        

Answer 1

The following will iterate through the memory of a structure. Only disadvantage is that it does a bytewise check.

#include 

struct Data { int i; bool b; };

template
bool IsAllZero(T const& data)
{
    auto pStart = reinterpret_cast(&data);
    for (auto pData = pStart; pData < pStart+sizeof(T); ++pData)
    {
        if (*pData)
            return false;
    }

    return true;
}

int main()
{
    Data data1;// = {0}; // will most probably have some content
    Data data2 = {0}; // all zeroes

    std::cout << "data1: " << IsAllZero(data1) << "\ndata2: " << IsEmptyStruct(data2);

    return 0;
};