Защита файла-сборки lib

if( now() > builtTime() + 60*60*24*15){ std::abort();}

#include <iostream>
#include <sstream>
#include <iomanip>
 
std::string build_time()
{
    return std::string(__DATE__) + " " + std::string(__TIME__);
}
 
std::tm make_build_time()
{
    std::tm tm_build;
 
    // example: 
    //std::istringstream ss("Jan 24 2016 19:08:48");
    std::istringstream ss(build_time());
 
    // convert format-string to tm
    ss >> std::get_time(&tm_build, "%b %d %Y %H:%M:%S");
 
    if (ss.fail())
        throw std::runtime_error("parse timestamp failed");
 
    return tm_build;
}
 
std::tm make_current_time()
{
    time_t rawtime;
    time(&rawtime);
    return *localtime(&rawtime);
}
 
int main()
{
    try{
 
        std::tm tm_build = make_build_time();
        std::tm tm_current = make_current_time();
 
        const double diff = difftime(mktime(&tm_current), mktime(&tm_build));
 
        std::cout << "build ...... "
            << std::put_time(&tm_build, "%b %d %Y %H:%M:%S") << '\n';
 
        std::cout << "current .... "
            << std::put_time(&tm_current, "%b %d %Y %H:%M:%S") << '\n';
 
        std::cout << "difftime ... " << diff << " seconds\n";
 
        if (diff >= 60)
            throw std::runtime_error("trial period complete");
        
        std::cout << "\ntime left: " << 60 - diff << " seconds\n";
        std::cout << "program successfully launched!\n";
 
    }
    catch (const std::runtime_error& e)
    {
        std::cout << "error: " << e.what() << std::endl;
    }
    catch (const std::exception e)
    {
        std::cout << "error: " << e.what() << std::endl;
    }
    catch (...)
    {
        std::cout << "unkown error" << std::endl;
    }
}