c++ - const-reference binding to a temporary -


consider following:

string const& name1 = get_name(...); string const  name2 = get_name(...);

where get_name returns string object. known, introduction of move-semantics in c++11, both statements can efficient, first 1 being more since move not need made. (yeah, know return-value optimization, it's more nuanced. general idea.)

however, suppose function calls left out of this:

string const& name3 {"billy"}; string const  name4 {"debbie"};

in case, string-literal "billy" implicitly converted temporary string, , name3 binds temporary. obviously, name4 not temporary.

is true name3 , name4, both equally efficient? seems me be...

name3 , name4 indistinguishable rest of program, unless use decltype(name3) or decltype(name4).

so compiler can generate same assembly both cases.

of course, general statement; individual compiler may generate slower or faster code , way find out try on compiler.


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