c++ - returning initializer list mechanism -

What mechanism is included, if the incoming type, which are created from the initial list, I do not specify that type While returning, such as:

  std :: arrays and lt; Int, 3 & gt; Make_array () {Return {1, 2, 3}; }   
 instead of  
  std :: arrays and lt; Int, 3 & gt; Make_array () {return std :: array & lt; Int, 3 & gt; {1, 2, 3}; }   
 If the initial list is returned without specifying a type, then does it contain any performance penalties? Am I really returning an array, which is the  std :: arrays    
 
 Does that change? 
 There is no performance penal in it. Return value  
  std :: arrays and lt; Int, 3 & gt; Has been made equal. X = {1, 2, 3};   
 No copy or a  std :: array  example is included