Incomplete types question
via Digitalmars-d-learn
digitalmars-d-learn at puremagic.com
Tue Jul 8 05:04:39 PDT 2014
On Tuesday, 8 July 2014 at 11:42:54 UTC, NoUseForAName wrote:
> On Tuesday, 8 July 2014 at 11:16:52 UTC, Marc Schütz wrote:
>> Your example above doesn't work, because it would be
>> interpreted as a redefinition of the struct. Instead, you can
>> use a public alias to a private type:
>>
>> // my_module.d:
>>
>> private struct MyStructImpl {
>> int x;
>> }
>>
>> public alias MyStructPtr = MyStructImpl*;
>>
>> void doSomething(MyStructPtr foo) {
>> ...
>> }
>>
>> // my_main_program.d:
>>
>> MyStructPtr bar; // OK
>> MyStructImpl foo; // Error: my_module.MyStructImpl is private
>
> Thanks, that is what I was looking for.
Addendum: You also need to protect the members of MyStructImpl,
like so:
private struct MyStructImpl {
private: // or `package:`
int x;
}
Otherwise, they would still be accessible via dereferencing.
(Don't worry, you _can_ access private members inside the module
the struct is declared in, as access protection in D only applies
across module boundaries.)
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