[gdal-dev] argument default value in the C API to GDALAlgorithmArg

[Even Rouault]

Chris,

why would you need it to be exposed ? If it is to workaround missing C 
API entry points, we should add them

Regarding struct GDALAlgorithmHS being exposed in gdalalgorithm.h, this 
is because another GDAL .cpp file needed it, but I think I should create 
instead a gdalalgorithm_priv.h header to move those struct definitions. 
Please don't rely on the internals of struct GDALAlgorithmHS

Even

Le 07/08/2025 à 06:44, Chris Toney a écrit :
> Hi Even,
>> If you need this in 3.11, you can define the following implementation
>> detail in your code
>>
>> struct GDALAlgorithmArgHS
> Could GDALAlgorithmArgHS be defined in gdalalgorithm.h (as struct
> GDALAlgorithmHS is)?
>
> Chris
>
>
> On Mon, Aug 4, 2025 at 2:42 AM Even Rouault <even.rouault at spatialys.com> wrote:
>> Hi Chris,
>>
>> This was indeed missing in the C API. Queued for 3.12 in
>> https://github.com/OSGeo/gdal/pull/12853
>>
>> If you need this in 3.11, you can define the following implementation
>> detail in your code
>>
>> struct GDALAlgorithmArgHS
>> {
>>       GDALAlgorithmArg *ptr = nullptr;
>>
>>       explicit GDALAlgorithmArgHS(GDALAlgorithmArg *arg) : ptr(arg)
>>       {
>>       }
>> };
>>
>> but better conditionalize it to 3.11 only, so that to avoid issues in
>> later version if we would change the definition of struct GDALAlgorithmArgHS
>>
>> and then do things like
>>
>> GDALAlgorithmArgH hArg;
>>
>> hArg->ptr->GetDefault<std::string>();
>>
>> Even
>>
>>
>> Le 04/08/2025 à 03:46, Chris Toney via gdal-dev a écrit :
>>> Hi,
>>> In the C API there is GDALAlgorithmArgHasDefaultValue(), but no
>>> interface to the GetDefault() class method to access the value itself
>>> when there is one (nor in the Python bindings, AFAICS).
>>>
>>> I don't believe there is a fromHandle() method on GDALAlgorithmArg to
>>> get to the C++ object.
>>>
>>> Is there possibly a workaround for that when working through the C API?
>>>
>>> Chris
>>> _______________________________________________
>>> gdal-dev mailing list
>>> gdal-dev at lists.osgeo.org
>>> https://lists.osgeo.org/mailman/listinfo/gdal-dev
>> --
>> http://www.spatialys.com
>> My software is free, but my time generally not.
>>
-- 
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