LOCALIZATION_ITEM(hello, "Привет")
LOCALIZATION_ITEM(bye,   "Пока")

LOCALIZATION_ITEM(hello, "Hello")
LOCALIZATION_ITEM(bye,   "Bye")

#ifndef LANG_ID
#   define LANG_ID__EN_US 0x0409
#   define LANG_ID__RU_RU 0x0419
#   define LANG_ID LANG_ID__RU_RU
#endif // LANG_ID


#if LANG_ID == LANG_ID__EN_US
#   include "langs\en-US.h"
#elif LANG_ID == LANG_ID__RU_RU
#   include "langs\ru-RU.h"
#endif

#ifndef LOCALIZATION_H
#define LOCALIZATION_H

#include <string>

namespace localization
{
    enum class msg_id
    {
        unknown = 0,

        #define LOCALIZATION_ITEM(id, message) id,
        #include "langs\current.h"
        #undef LOCALIZATION_ITEM
    };

    std::string message(msg_id id);

} // namespace localization

#endif // LOCALIZATION_H

#include <exception>

#include "localization.h"

namespace localization
{
    std::string message(msg_id id)
    {
        switch (id)
        {
        case msg_id::unknown:
            return std::string();

        #define LOCALIZATION_ITEM(id, message) case msg_id::id: return std::string(message);
        #include "langs\current.h"
        #undef LOCALIZATION_ITEM

        default:
            throw std::runtime_error("bad msg_id");
        }
    }
    
} // namespace localization

#include <iostream>

#include "localization.h"

int main(int, char**)
{
    std::cout << localization::message(localization::msg_id::hello) << std::endl;
    std::cout << localization::message(localization::msg_id::bye) << std::endl;

    return 0;
}