to_chars.cc

#include <charconv>
#include <iostream>
#include <string>
#include <system_error>

std::string to_hex(uint64_t val) {
  char buf[16];
  auto [end, e] = std::to_chars(std::begin(buf), std::end(buf), val, 16);
  if (e != std::errc()) {
    throw std::system_error(std::make_error_code(e));
  }
  return {buf, end};
}

int main() {
  try {
    std::cout << to_hex(0x1234'DEAD'BEEF) << std::endl;
    return EXIT_SUCCESS;
  } catch (const std::system_error& e) {
    std::cerr << e.what() << std::endl;
    return EXIT_FAILURE;
  }
}