Question

I have a unsigned c++ char buffer

unsigned char* pBuffer =  new unsigned char [1024];

I want to save the pBuffer pointer in the first few bytes of the newly allocated buffer by using an assignement rather than memcpy- ie

*(unsigned char*) &pBuffer[0] = pBuffer;

I am not able to get the sytax right. Appreciate help with the correct syntax for doing this.

Visual Studio 2010

Answer 1

I don’t know why you would want to do this, but I can think of a few oddball reasons, so:

reinterpret_cast<unsigned char**>(pBuffer)[0] = pBuffer;

You want the compiler to reinterpret the pointer as a unsigned char**, and store the value of pBuffer in the 0-index slot.

You said you’re indexing a “linked list” with multiple pBuffers. In that case, you should not use reinterpret_cast. Instead:

struct node {
     node* prev;
     std::unique_ptr<node> next;
     unsigned char buffer[1024];
     node(node* prev_) : prev(prev_) {}
};

std::unique_ptr<node> list(new node(nullptr)); //tada