Re: Strict aliasing, is it OK?

[Simon Wright <simon@pushface.org>]

Victor Porton <porton@narod.ru> writes:

>    type My_Dummy_Access is access constant RDF.Auxiliary.Dummy_Record;
>
>    function C_Raptor_Parser_Get_Description (Parser: Handle_Type) return My_Dummy_Access
>       with Import, Convention=>C, External_Name=>"raptor_parser_get_description";
>
>    function Get_Description (Parser: Parser_Type) return RDF.Raptor.Syntaxes.Syntax_Description_Type is
>       function Conv is new Ada.Unchecked_Conversion(My_Dummy_Access, RDF.Raptor.Syntaxes.Syntax_Description_Type);

(I _wish_ you could use shorter lines!)

Is an "RDF.Raptor.Syntaxes.Syntax_Description_Type" actually an "access
constant RDF.Auxiliary.Dummy_Record"? If so, why not just declare
C_Raptor_Parser_Get_Description as returning a
RDF.Raptor.Syntaxes.Syntax_Description_Type? And if not, what are you
doing returning an unchecked conversion of one to the other?

Your code as it stands is equivalent to

   function C_Raptor_Parser_Get_Description
     (Parser : Handle_Type)
     return RDF.Raptor.Syntaxes.Syntax_Description_Type
      with
        Import,
        Convention => C,
        External_Name => "raptor_parser_get_description";