How to share global constants with minimum overhead at runtime?

Question

I am using C++11. I am not allowed to use external libraries like boost etc. I must use STL only.

I have a number of events, which must be identified as string const

Answer 1

In light of the fact that you're stuck with C++11, I think my suggestion from here still stands:

#ifndef INCLUDED_EVENT_NAMES
#define INCLUDED_EVENT_NAMES

#pragma once

namespace event_names
{
    constexpr auto& event_1 = "event_1";
    constexpr auto& event_2 = "event_2";
}

#endif

Defining named references to string literal objects is very simple, does not require any additional libraries, is guaranteed to not introduce any unnecessary objects, won't require any additional memory over the storage for the statically-allocated string literal objects that you'd need anyways, and will not have any runtime overhead.

If you could use C++17, I'd suggest to go with the std::string_view approach, but in C++11, I think the above is most-likely a good compromise for your application.