How can I convert const std::vector<unsigned char> to char

Question

What would be the correct way to convert from unsigned char std::vector to char?

void SendSocket(const std::vector<BYTE> &buffer)
{
    int ret;
    const BYTE* bufferPtr = &buffer[0];
    ret = send(_socket, (const char*)bufferPtr, buffer.size(), 0);
}

Answer 1

Assuming that BYTE is a typedef for char (with or without signed or unsigned ), then your code is fine, but slightly more verbose than necessary. The storage used by a vector is required to be a contiguous array, so taking the address of the first element gives you a pointer to that array. Any kind of char has the same layout and alignment as any other kind of char , so the pointer conversion is valid.

The argument to send is const void* , and (more or less) any pointer can be converted to that implicitly, so there's no need to cast:

ret = send(_socket, &buffer[0], buffer.size(), 0);

However, you should check (or otherwise ensure) that buffer isn't empty before using [] .