• cal (10/10) Mar 28 2013 Given:
• Andrej Mitrovic (7/11) Mar 28 2013 void main()
• cal (5/6) Mar 28 2013 Yeh this is the problem. I can map data layout of complex
• cal (4/6) Mar 28 2013 Just realized that format.d is able to figure it out, since it
• Andrej Mitrovic (7/10) Mar 28 2013 Ah, I didn't even know .tupleof would contain .offsetof.

"cal" <callumenator gmail.com> writes:

Given:

struct S {
   union {
     int i;
     float f;
   }
}

is there any way to detect the fact that fields i and f will have 
the same offset from S? (Creating an instance of S and getting 
the relative addresses only works if the union is public).

"Andrej Mitrovic" <andrej.mitrovich gmail.com> writes:

On Thursday, 28 March 2013 at 20:02:18 UTC, cal wrote:
 is there any way to detect the fact that fields i and f will 
 have the same offset from S?

void main()
{
     static if (S.init.i.offsetof == S.init.f.offsetof)
         pragma(msg, "Union");
}

 (Creating an instance of S and getting the relative addresses 
 only works if the union is public).

.offsetof will also require access rights to the fields.

"cal" <callumenator gmail.com> writes:

On Thursday, 28 March 2013 at 20:18:45 UTC, Andrej Mitrovic wrote:
 .offsetof will also require access rights to the fields.

Yeh this is the problem. I can map data layout of complex 
aggregates, even if the members are private, but unions mess that 
up. Restricting to public fields is an option, but i'd like to be 
able to get it all.

"cal" <callumenator gmail.com> writes:

On Thursday, 28 March 2013 at 20:18:45 UTC, Andrej Mitrovic wrote:
 On Thursday, 28 March 2013 at 20:02:18 UTC, cal wrote:
 .offsetof will also require access rights to the fields.

Just realized that format.d is able to figure it out, since it 

regardless of protection. Thanks

Andrej Mitrovic <andrej.mitrovich gmail.com> writes:

On 3/28/13, cal <callumenator gmail.com> wrote:
 Just realized that format.d is able to figure it out, since it

 regardless of protection. Thanks

Ah, I didn't even know .tupleof would contain .offsetof.

void main()
{
    static if (S.tupleof[0].offsetof == S.tupleof[1].offsetof)
        pragma(msg, "Union");
}