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

Simply increase your pointer to your start index.

Example

const unsigned char * src = reinterpret_cast(your source);
unsigned char * dest = reinterpret_cast(your dest);
memcpy(dest, src + offset, len);

What about using STL collections to avoid memory access errors?