#if (FOR_ALTERNATIVE == 0)
    for (std::vector<Project*>::iterator it = projects_to_update.begin(); it != projects_to_update.end(); ++it) {
        Project* p = *it;
        p->contact_scheduler();
    }
#elif (FOR_ALTERNATIVE == 1)
    for (auto it = projects_to_update.begin(); it != projects_to_update.end(); ++it) {
        Project* p = *it;
        p->contact_scheduler();
    }
#elif (FOR_ALTERNATIVE == 2)
    for (Project* p : projects_to_update) {
        p->contact_scheduler();
    }
#elif (FOR_ALTERNATIVE == 3)
    class Updater {
        void operator()(Project* p) const { p->contact_scheduler(); }
    };
    std::for_each(projects_to_update.begin(), projects_to_update.end(), Updater());
#elif (FOR_ALTERNATIVE == 4)
    std::for_each(projects_to_update.begin(), projects_to_update.end(), sigc::mem_fun(&Project::contact_scheduler));
#endif