https://jlospinoso.github.io/c++/developing/software/visual%20studio/2015/02/16/aligning-bytes-in-vs2013.html

main.cpp

#include <iostream>
#include <memory>
#include "MemoryPrinter.h"

#define MEM_SIZE 32
#define HEADER "\x01\x02\x03\x04\x05\x06\x07\x08\x09"
#define HEADER_LENGTH 9
#define ALIGNMENT 8
#define BUFFER "\x10\x11\x12\x13\x14\x15\x16\x17"
#define BUFFER_LENGTH 8

void print(void *start, int length) {
	int index = 0;
	char *startAsChar = (char*)start;

	printf("%u bytes starting at %x:\n", length, start);
	while (index < length){
		printf("%03u: ", index);
		for (int column = 0; index < length && column < ALIGNMENT; column++, index++){
			printf("0x%02x ", *(startAsChar + index));
		}
		printf("\n");
	}
}

int main() {
	char data[MEM_SIZE] = { 0 };
	memcpy(data, HEADER, HEADER_LENGTH);
	print(data, MEM_SIZE);

	void *endOfHeader = &(data[0]) + HEADER_LENGTH;
	std::size_t space = MEM_SIZE - HEADER_LENGTH;
	void *nextAvailableByte = std::align(ALIGNMENT, BUFFER_LENGTH, endOfHeader, space);
	memcpy(nextAvailableByte, BUFFER, BUFFER_LENGTH);

	print(data, MEM_SIZE);
}