acces to nested struc/unit member

[Derek Parnell]

On Fri, 29 Dec 2006 14:52:59 +0000 (UTC), novice2 wrote:

> Hello. Could please anybody explain me syntax to access to nested
> structure/union members? In Windows API translated headers thearis
> situation - anonimous union nested in structure. This is minimal
> trivial extracted example:
> 
> //dmd\html\d\struct.html: "anonymous structs/unions are allowed as
> members of other structs/unions"
> 
> struct Stru
> {
>   int a;
>   union Uni
>   {
>     int b;
>     int c;
>   };
> }
> 
> 
> void main()
> {
>   Stru s;
> 
>   //s.Uni.b = 2; // Error: need 'this' to access member b
> 
>   //s.b = 2;     // Error: no property 'b' for type 'Stru'
>                  // Error: constant (s).b is not an lvalue
> }
> 
> 
> How i can access to s.Uni.b ?
> Thanks for any advises.

Either use anonymous struct or declare and instance of the struct.

Eg. (Anonymous)

 struct Stru
 {
   int a;
   union  // Don't give this a name.
   {
     int b;
     int c;
   };
 }
 
 
 void main()
 {
   Stru s;
   s.b = 2;
 }


Eg. (Named)

 struct Stru
 {
   int a;
   union  Uni // Named, therefore must instantiate it.
   {
     int b;
     int c;
   };
   Uni u;
 }
 
 
 void main()
 {
   Stru s;
   s.u.b = 2;
 }

-- 
Derek Parnell