Dear all,

I was trying to invoke some D code from Python and ran into issues which I eventually traced back to a simple example on the D website itself :

https://dlang.org/articles/dll-linux.html

Particularly the section "Dynamically Loading a D DLL From a C Program"

In my case, and indeed already in 2013 (https://forum.dlang.org/post/yeqyqaaguhngczlnvqnq@forum.dlang.org), shared static this does not get invoked

I normally use:
LDC - the LLVM D compiler (1.21.0):
  based on DMD v2.091.1 and LLVM 10.0.0   (under Linux)

but I also tried
DMD64 D Compiler v2.095.0

Is the solution suggested in the linked post the "canonical way"?

Where could one file a suggestion for an update to the documentation?

Cheers!

PS Enjoying my project in D especially how easy it is to get the same code to run under windows too

On Tuesday, 12 January 2021 at 08:19:45 UTC, ichneumwn wrote:
> Where could one file a suggestion for an update to the documentation?

In the top right section of the page you can click the "Improve this page"-link.

On Tuesday, 12 January 2021 at 08:19:45 UTC, ichneumwn wrote:
> Dear all,
>
> I was trying to invoke some D code from Python and ran into issues which I eventually traced back to a simple example on the D website itself :
>
> https://dlang.org/articles/dll-linux.html
>
> Particularly the section "Dynamically Loading a D DLL From a C Program"
>
> In my case, and indeed already in 2013 (https://forum.dlang.org/post/yeqyqaaguhngczlnvqnq@forum.dlang.org), shared static this does not get invoked
>
> I normally use:
> LDC - the LLVM D compiler (1.21.0):
>   based on DMD v2.091.1 and LLVM 10.0.0   (under Linux)
>
> but I also tried
> DMD64 D Compiler v2.095.0
>
> Is the solution suggested in the linked post the "canonical way"?
>
> Where could one file a suggestion for an update to the documentation?
>
> Cheers!
>
> PS Enjoying my project in D especially how easy it is to get the same code to run under windows too

Follow on to my own question: on Linux, with gcc, I have created the following file "starter.c" that I inject into my D shared library:

  int rt_init(void);
  int rt_term(void);

  // should really check for errors!
  static void __attribute__((constructor)) Dstarter(void) {
    rt_init();
  }

  static void __attribute__((destructor)) Dterminator(void) {
    rt_term();
  }

That seems to do the trick. Not sure how clean this is?

On Tuesday, 12 January 2021 at 09:31:08 UTC, ichneumwn wrote:

>
> Follow on to my own question: on Linux, with gcc, I have created the following file "starter.c" that I inject into my D shared library:
>
>   int rt_init(void);
>   int rt_term(void);
>
>   // should really check for errors!
>   static void __attribute__((constructor)) Dstarter(void) {
>     rt_init();
>   }
>
>   static void __attribute__((destructor)) Dterminator(void) {
>     rt_term();
>   }
>
> That seems to do the trick. Not sure how clean this is?

You should be able to do the same in D with `pragma(crt_constructor)` and `pragma(crt_destructor)`:

https://dlang.org/spec/pragma.html#crtctor
https://dlang.org/spec/pragma.html#crtdtor
https://dlang.org/changelog/2.078.0.html#crt-constructor

On Tuesday, 12 January 2021 at 09:49:46 UTC, Mike Parker wrote:
> On Tuesday, 12 January 2021 at 09:31:08 UTC, ichneumwn wrote:
>
>>
>> Follow on to my own question: on Linux, with gcc, I have created the following file "starter.c" that I inject into my D shared library:
>>
>>   int rt_init(void);
>>   int rt_term(void);
>>
>>   // should really check for errors!
>>   static void __attribute__((constructor)) Dstarter(void) {
>>     rt_init();
>>   }
>>
>>   static void __attribute__((destructor)) Dterminator(void) {
>>     rt_term();
>>   }
>>
>> That seems to do the trick. Not sure how clean this is?
>
> You should be able to do the same in D with `pragma(crt_constructor)` and `pragma(crt_destructor)`:
>
> https://dlang.org/spec/pragma.html#crtctor
> https://dlang.org/spec/pragma.html#crtdtor
> https://dlang.org/changelog/2.078.0.html#crt-constructor

Perfect, thanks! Interestingly, as I removed the C stub and tried the D route, I noticed that just calling rt_init() is enough to also get static ~this() to run on exit. In fact then adding writeln in a pragma(crt_destructor) function shows that it gets called after static ~this().

For anyone stumbling across this thread and looking for the import for rt_init/term:

import core.runtime : rt_init, rt_term;

On Tuesday, 12 January 2021 at 09:02:38 UTC, Imperatorn wrote:
> On Tuesday, 12 January 2021 at 08:19:45 UTC, ichneumwn wrote:
>> Where could one file a suggestion for an update to the documentation?
>
> In the top right section of the page you can click the "Improve this page"-link.

Thanks, I will leave it though. I do not want to mess about and write about something I have just learnt in the last hour. That could do more damage than good.