C에서 파일을 복사하는 가장 효율적이고 안전한 방법은 무엇입니까?

#include <iostream>
#include <fstream>

int main() {
  std::ifstream source("from.ogv", std::ios::binary);
  std::ofstream destination("to.ogv", std::ios::binary);
  destination << source.rdbuf();
}

#include <fcntl.h>
#include <unistd.h>

int main() {
  int source = open("from.ogv", O_RDONLY, 0);
  int destination = open("to.ogv", O_WRONLY | O_CREAT, 0644);
  char buffer[BUFSIZ];
  while ((size_t)read(source, buffer, BUFSIZ) > 0) {
    write(destination, buffer, size);
  }
}

#include <sys/mman.h>
#include <sys/stat.h>
#include <fcntl.h>

int main() {
  int source = open("from.ogv", O_RDONLY, 0);
  int destination = open("to.ogv", O_WRONLY | O_CREAT, 0644);
  struct stat stat_source;
  fstat(source, &stat_source);
  char *source_ptr = (char *)mmap(NULL, stat_source.st_size, PROT_READ, MAP_PRIVATE, source, 0);
  char *destination_ptr = (char *)mmap(NULL, stat_source.st_size, PROT_WRITE, MAP_PRIVATE, destination, 0);
  memcpy(destination_ptr, source_ptr, stat_source.st_size);
}

#include <boost/filesystem.hpp>

int main() {
  boost::filesystem::copy_file("from.ogv", "to.ogv", boost::filesystem::copy_option::overwrite_if_exists);
}