Preventing writes to a global struct instance with const?

[Bill Baxter]

Bradley Smith wrote:
> Rick Mann wrote:
>> I have an external variable declared like this:
>>
>> struct
>> ControlID
>> {
>>     uint            signature;
>>     int                id;
>> };
>> extern extern (C) const HIViewID kHIViewWindowContentID;
>>
>> But when I am able to write code like this without complaint from the 
>> compiler (GDC 0.21/DMD 1.00):
>>
>> kHIViewWindowContentID.signature = 123;
>>
>> I'd like to prevent that. Is such a thing possible?
>>
> 
> Why doesn't private protection work on structs? I tested it with DMD 
> 1.003 and was surprised by the result.
> 
> struct ControlID {
>   private uint signature_;
>   private int id_;
>     
>   uint signature() {
>     return signature_;
>   }
> }
> 
> void main() {
>   ControlID id;
>   id.signature = 123;  // Compiler error
>   uint i = id.signature;
> 
>   id.signature_ = 123;  // Doesn't fail. Should it?
> }

Isn't that because protection attributes are applied at the module 
level, not class/struct level?

--bb