memcpy with startIndex?

Question

I wish to copy content of specific length from one buffer to another from a specific starting point. I checked memcpy() but it takes only the length of content

Answer 1

If you're using c++, it is probably better to use std::copy() instead of memcpy(). std::copy can take pointers just as easily as iterators.

e.g.

int src[20];
int dst[15];

// Copy last 10 elements of src[] to first 10 elements of dst[]
std::copy( src+10, src+20, dst );

As with memcpy(), it's your responsibility to make sure the pointers are valid.

NOTE. If your usage is performance critical you may find a memcpy() as detailed in the other answers quicker, but probably not by much.