This is my first time on the Dlang forum. I like the language but my usecase is a bit different.

I want to write Postgresql extension in D. Currently extension can be written in C or C linked languages. Has anyone done this or can point me to some code.

Thanks

On Thursday, 15 November 2018 at 13:05:59 UTC, Ranjan wrote:
> This is my first time on the Dlang forum. I like the language but my usecase is a bit different.
>
> I want to write Postgresql extension in D. Currently extension can be written in C or C linked languages. Has anyone done this or can point me to some code.
>
> Thanks

Did you read this: https://dlang.org/spec/interfaceToC.html ?

Andrea

On Thursday, 15 November 2018 at 17:03:55 UTC, Andrea Fontana wrote:
> On Thursday, 15 November 2018 at 13:05:59 UTC, Ranjan wrote:
>> This is my first time on the Dlang forum. I like the language but my usecase is a bit different.
>>
>> I want to write Postgresql extension in D. Currently extension can be written in C or C linked languages. Has anyone done this or can point me to some code.
>>
>> Thanks
>
> Did you read this: https://dlang.org/spec/interfaceToC.html ?
>
> Andrea

Yes, but it's not useful, in Postgesql extension C code needs to call D, without GarbageCollection. I am able to do this in RustLang but I am not sure how to in D, as it has a GC. Looking for examples from the community.

Thanks

On 16/11/2018 3:18 PM, Ranjan wrote:
> On Thursday, 15 November 2018 at 17:03:55 UTC, Andrea Fontana wrote:
>> On Thursday, 15 November 2018 at 13:05:59 UTC, Ranjan wrote:
>>> This is my first time on the Dlang forum. I like the language but my usecase is a bit different.
>>>
>>> I want to write Postgresql extension in D. Currently extension can be written in C or C linked languages. Has anyone done this or can point me to some code.
>>>
>>> Thanks
>>
>> Did you read this: https://dlang.org/spec/interfaceToC.html ?
>>
>> Andrea
> 
> Yes, but it's not useful, in Postgesql extension C code needs to call D, without GarbageCollection. I am able to do this in RustLang but I am not sure how to in D, as it has a GC. Looking for examples from the community.
> 
> Thanks

There isn't anything special you need to learn.
As long as you don't mutate anything you receive via the GC or send any GC owned memory outside of D, you'll have an easy time of it.

On Friday, 16 November 2018 at 02:18:11 UTC, Ranjan wrote:
> On Thursday, 15 November 2018 at 17:03:55 UTC, Andrea Fontana wrote:
>> On Thursday, 15 November 2018 at 13:05:59 UTC, Ranjan wrote:
>>> This is my first time on the Dlang forum. I like the language but my usecase is a bit different.
>>>
>>> I want to write Postgresql extension in D. Currently extension can be written in C or C linked languages. Has anyone done this or can point me to some code.
>>>
>>> Thanks
>>
>> Did you read this: https://dlang.org/spec/interfaceToC.html ?
>>
>> Andrea
>
> Yes, but it's not useful, in Postgesql extension C code needs to call D, without GarbageCollection. I am able to do this in RustLang but I am not sure how to in D, as it has a GC. Looking for examples from the community.
>
> Thanks

There is -betterC [1] compiler flag that allows one to code without the D runtime and create programs that depend only on the C runtime, so there is no GC - and no GC related functionality also.

You probably want to try this route for creating the extension, as it will be simpler if you know C and the Postgres API.

1. https://dlang.org/spec/betterc.html

On Friday, 16 November 2018 at 02:18:11 UTC, Ranjan wrote:
> On Thursday, 15 November 2018 at 17:03:55 UTC, Andrea Fontana wrote:
>> On Thursday, 15 November 2018 at 13:05:59 UTC, Ranjan wrote:
>>> This is my first time on the Dlang forum. I like the language but my usecase is a bit different.
>>>
>>> I want to write Postgresql extension in D. Currently extension can be written in C or C linked languages. Has anyone done this or can point me to some code.
>>>
>>> Thanks
>>
>> Did you read this: https://dlang.org/spec/interfaceToC.html ?
>>
>> Andrea
>
> Yes, but it's not useful, in Postgesql extension C code needs to call D, without GarbageCollection. I am able to do this in RustLang but I am not sure how to in D, as it has a GC. Looking for examples from the community.
>
> Thanks

I'm not an exert with C nor D. So I might misuderstand the issue... You can write a skeleton plugin for postgres in C that at init time starts the D runtime. From then on your C skelton plugin can call some function in D.