[postgis-devel] Is posible to use function lwgeom_to_geojson in another c fuctions

[Nicklas Aven]

Just a comment.
With all the new json functions in PostgreSQL this is very easy to do directly in sql too. I think it is fairly efficient too. I use it in production to export complete geojson through postgrest.

I have thougt about if we could get rid of json-c dependency and use postgresql functionality instead. 
Building json with jsonb, I guess is a lot faster than dealing with text strings.

/Nicklas

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---- Jan Michálek skrev ----

> Hello
> 
> I need a advice about this problem
> 
> I'm trying to write some C fuction for making geojson as aggregate from records as full regular geojson with properties.
> 
> I tried to use function lwgeom_to_geojson inside my code.
> 
> something like this
> 
>                 case JSONTYPE_GEOM: //je;
>                         {
>                         LWGEOM *lwgeom;
>                         lwgeom = lwgeom_from_gserialized(
>                              (GSERIALIZED*)DatumGetPointer(val)
>                               );
>                         outputstr = lwgeom_to_geojson(lwgeom, 0, 0, false);
>                         escape_json(result, outputstr);
>                         pfree(outputstr);
> 
>                         break;
> 
>                         }
> 
> 
> 
> I have 
> #include "liblwgeom.h"
> 
> And I`m able to compile this. But if I try use function in postgre, it get me an error
> 
> ERROR:  could not load library "/usr/lib/postgresql/jelejson.so": /usr/lib/postgresql/jelejson.so: undefined symbol: lwgeom_to_geojson.
> 
> What i should do? Is posible to use this function like this?
> 
> Thanks Je;
> 
> 
> -- 
> 
> Jelen
> 
> Starší čeledín datovýho chlíva
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