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import issue?
Nov 22, 2023
DLearner
Nov 22, 2023
DLearner
Nov 22, 2023
DLearner
November 22, 2023
Gravatar of DLearnerPosted by DLearnerReply
DLearner
Gravatar of DLearner


Reply

Please,
Why does:

// Test module Ex_mod
struct SA {
   int   SAIntFld1;
   int   SAIntFld2;
}

bool AddEle(ref void* StartPtr, SA PayLoad1) {

   import core.stdc.stdlib : malloc;

   struct Ele {
      SA   PayLoad;
      Ele* EleNxtPtr;
      Ele* ElePrvPtr;
   }

   Ele*    ElePtr;
   Ele*  wkElePtr;

   return true;
}

imported into:

// Test harness

struct SA {
   int   SAIntFld1;
   int   SAIntFld2;
}


void main() {

   import std.stdio: writeln;

   import Ex_mod;

   SA SAVar;
   void* SA_StartPtr = null;

   SAVar.SAIntFld1 = 3;
   SAVar.SAIntFld2 = -5;

   if (AddEle(SA_StartPtr, SAVar)) {
      writeln("Element linked");
   } else {
      writeln("Element not linked");
   }

}

Fail with:

ex_main.d(21): Error: function `Ex_mod.AddEle(ref void* StartPtr, SA PayLoad1)` is not callable using argument types `(void*, SA)`
ex_main.d(21):        cannot pass argument `SAVar` of type `ex_main.SA` to parameter `Ex_mod.SA PayLoad1`

When eliminating the import via:

// Test harness

struct SA {
   int   SAIntFld1;
   int   SAIntFld2;
}

bool AddEle(ref void* StartPtr, SA PayLoad1) {

   import core.stdc.stdlib : malloc;

   struct Ele {
      SA   PayLoad;
      Ele* EleNxtPtr;
      Ele* ElePrvPtr;
   }

   Ele*    ElePtr;
   Ele*  wkElePtr;

   return true;
}


void main() {

   import std.stdio: writeln;

//   import Ex_mod;

   SA SAVar;
   void* SA_StartPtr = null;

   SAVar.SAIntFld1 = 3;
   SAVar.SAIntFld2 = -5;

   if (AddEle(SA_StartPtr, SAVar)) {
      writeln("Element linked");
   } else {
      writeln("Element not linked");
   }

}

works correctly?

November 23, 2023
Gravatar of Richard (Rikki) Andrew CattermolePosted by Richard (Rikki) Andrew Cattermole
in reply to DLearner		Reply
Richard (Rikki) Andrew Cattermole
Gravatar of Richard (Rikki) Andrew Cattermole
Posted in reply to DLearner


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You have two ``SA`` structs, each in different encapsulations.

Each of them are different, even if they have similar members.

In D types that look the same do not combine, they are distinct.

You can see this by comparing the mangling of each.

``pragma(msg, SA.mangleof);``
November 22, 2023
Gravatar of DLearnerPosted by DLearner
in reply to Richard (Rikki) Andrew Cattermole		Reply
DLearner
Gravatar of DLearner
Posted in reply to Richard (Rikki) Andrew Cattermole


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On Wednesday, 22 November 2023 at 16:11:03 UTC, Richard (Rikki) Andrew Cattermole wrote:
> You have two ``SA`` structs, each in different encapsulations.
>
> Each of them are different, even if they have similar members.
>
> In D types that look the same do not combine, they are distinct.
>
> You can see this by comparing the mangling of each.
>
> ``pragma(msg, SA.mangleof);``

Is the encapsulation issue resolved if the struct itself is held in another module, and imported from that module into both the 'main' and 'Ex_mod' files?
November 23, 2023
Gravatar of Richard (Rikki) Andrew CattermolePosted by Richard (Rikki) Andrew Cattermole
in reply to DLearner		Reply
Richard (Rikki) Andrew Cattermole
Gravatar of Richard (Rikki) Andrew Cattermole
Posted in reply to DLearner


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On 23/11/2023 5:34 AM, DLearner wrote:
> Is the encapsulation issue resolved if the struct itself is held in another module, and imported from that module into both the 'main' and 'Ex_mod' files?

Each module is its own encapsulation unit.

As long as you are using the same distinct type in both modules, the issues are resolved.

Where the distinct type is defined does not matter for matching of function parameters.
November 22, 2023
Gravatar of DLearnerPosted by DLearner
in reply to Richard (Rikki) Andrew Cattermole		Reply
DLearner
Gravatar of DLearner
Posted in reply to Richard (Rikki) Andrew Cattermole


Reply
On Wednesday, 22 November 2023 at 16:51:54 UTC, Richard (Rikki) Andrew Cattermole wrote:
> On 23/11/2023 5:34 AM, DLearner wrote:
>> Is the encapsulation issue resolved if the struct itself is held in another module, and imported from that module into both the 'main' and 'Ex_mod' files?
>
> Each module is its own encapsulation unit.
>
> As long as you are using the same distinct type in both modules, the issues are resolved.
>
> Where the distinct type is defined does not matter for matching of function parameters.

OK thanks.