Is it safe to return a static string_view created from a string literal?

Question

I have a relatively simple use case: I want to associate a trait to a class which will return some user defined string, namely some user-defined registration ID. As this registrations are supposed to be defined at compile-time I would like it to be constexpr so I wrote something like the following:

template <typename T>
struct ClassRegistration
{
    static constexpr std::string_view
    Name();
};

template <>                                                                                    
struct ClassRegistration<int>                                                            
{                                                                                              
    static constexpr std::string_view                                                        
    Name()                                                                                     
    {                                                                                          
        return std::string_view{ "int" };                                                     
    }                                                                                          
};

https://godbolt.org/z/5p8xkA

Everything is working fine but as string_view doesn't actually own its buffer I wonder if it's guaranteed to be safe, that I'm not just referring to a dangling pointer. From what I read string literals are guaranteed to have the lifetime as long as that of the program itself (from this SO Lifetime of a string literal returned by a function).

Therefore, is this usage of string_view safe and appropriate?

https://stackoverflow.com/questions/45666043/c-standard-odr-and-constexpr-stdstring-view — NoSenseEtAl, Jun 04 '20 at 11:03
@NoSenseEtAl `static constexpr` variables at class scope are implicitly `inline`, so it shouldn't apply here. — HolyBlackCat, Jun 04 '20 at 11:05
@HolyBlackCat I know, but I understand how link could be confusing for somebody who does not know that... — NoSenseEtAl, Jun 04 '20 at 11:11
Thank you @NoSenseEtAl, luckily that part was pretty clear already — Triskeldeian, Jun 04 '20 at 16:07

score 10 · Accepted Answer · answered Jun 04 '20 at 11:05

10

string literals are guaranteed to have the lifetime as long as that of the program itself

That's correct.

Therefore, is this usage of string_view safe and appropriate?

Yes, your code is fine.

answered Jun 04 '20 at 11:05

HolyBlackCat

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Is it safe to return a static string_view created from a string literal?

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