The C++11 way to convert from string to wstring and back

+to_wstring.cc

template <typename Codecvt = std::codecvt_utf8<wchar_t>>
inline std::wstring to_wstring(const std::string& s)
{
  std::wstring_convert<Codecvt> conv;
  return conv.from_bytes(s);
}

.gitignore

build
build_win
to_wstring
*.exe
*.ilk
*.pdb

BUILD_AND_RUN.md

GNU/Linux:

cmake -S . -B build && cmake --build build && ./to_wstring

Windows:

cmake -S . -B build_win -G Ninja && cmake --build build_win && .\to_wstring

CMakeLists.txt

cmake_minimum_required(VERSION 3.16)

project(
    to_wstring
    VERSION 0.1.0
    DESCRIPTION
        "The C++11 way to convert from string to wstring and back"
    HOMEPAGE_URL
        https://gist.github.com/phetdam/36d2312e6bd652b7a8b58260f5368d86
    LANGUAGES CXX
)

# technically, <codecvt> is deprecated in C++17, but sadly there isn't a
# suitable standard library replacement for it yet
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

add_executable(to_wstring to_wstring.cc)
set_property(
    TARGET to_wstring
    PROPERTY RUNTIME_OUTPUT_DIRECTORY ${CMAKE_SOURCE_DIR}
)

to_wstring.cc

/**
 * @file to_wstring.cc
 * @author Derek Huang
 * @brief The C++11 way to convert from string to wstring and back
 * @copyright MIT License
 */

#include <codecvt>
#include <cstdlib>
#include <locale>
#include <iostream>
#include <memory>

namespace {

/**
 * Return a `std::wstring` from a `std::string`.
 *
 * @tparam Codecvt `std::codecvt` facet, default `std::codecvt_utf8<wchar_t>`
 *
 * @param s `const std::string&` string to convert
 */
template <typename Codecvt = std::codecvt_utf8<wchar_t>>
inline std::wstring to_wstring(const std::string& s)
{
  std::wstring_convert<Codecvt> conv;
  return conv.from_bytes(s);
}

/**
 * Return a `std::string` from a `std::wstring`.
 *
 * @tparam Codecvt `std::codecvt` facet, default `std::codecvt_utf8<wchar_t>`
 *
 * @param ws `const std::wstring&` wide string to convert
 */
template <typename Codecvt = std::codecvt_utf8<wchar_t>>
inline std::string from_wstring(const std::wstring& ws)
{
  std::wstring_convert<Codecvt> conv;
  return conv.to_bytes(ws);
}

}  // namespace

#define PDGIST_MY_STRING "this is my string"

int main()
{
  std::cout << "to_wstring(\"" PDGIST_MY_STRING "\") -- ";
  if (to_wstring(PDGIST_MY_STRING) == L"" PDGIST_MY_STRING)
    std::cout << "success\n";
  else
    std::cout << "failure\n";
  std::cout << "to_string(L\"" PDGIST_MY_STRING "\") -- ";
  if (from_wstring(L"" PDGIST_MY_STRING) == PDGIST_MY_STRING)
    std::cout << "success" << std::endl;
  else
    std::cout << "failure" << std::endl;
  return EXIT_SUCCESS;
}