Hi, Thanks.
We need to implement garrow_field_get_meatadata(), garrow_field_with_metadata() and garrow_field_with_merged_metadata(). I'll do it before Apache Arrow 3.0.0. So you can't read extension type for now. Sorry. Thanks, -- kou In <cs1pr8401mb0822a99d196dd438b14d6d22eb...@cs1pr8401mb0822.namprd84.prod.outlook.com> "Re: [C-Glib] - writing an extension array" on Fri, 27 Nov 2020 05:15:56 +0000, Ishan Anand <[email protected]> wrote: > Hi Kou > > Sure. Here are the code snippets as a github gist - > https://gist.github.com/ananis25/0b645ef94a70a0834fd23177e8721be9 > > Thank you for looking. > > > ________________________________ > From: Sutou Kouhei <[email protected]> > Sent: Friday, November 27, 2020 8:41 AM > To: [email protected] <[email protected]> > Subject: Re: [C-Glib] - writing an extension array > > Hi, > > Could you provide the Python script you used and the C > program you used? > > > Thanks, > -- > kou > > In > > <cs1pr8401mb082208b574a83aff774f617ceb...@cs1pr8401mb0822.namprd84.prod.outlook.com> > "[C-Glib] - writing an extension array" on Thu, 26 Nov 2020 18:11:53 +0000, > Ishan Anand <[email protected]> wrote: > >> Hi >> >> How do you go about implementing an extension type through the C API for >> Arrow? >> >> Creating a record batch in python like the example in pyarrow tests >> [here](https://github.com/apache/arrow/blob/2a5f92455ec4f9788ee96fa209b38d76bd927196/python/pyarrow/tests/test_extension_type.py#L375), >> and reading the resulting schema using the C API, it correctly reads it as >> an array of the underlying storage type. The schema along with the metadata >> can be printed as expected. >> ``` >> ext: int64 >> -- metadata -- >> ARROW:extension:metadata: freq=D >> ARROW:extension:name: test.period >> ``` >> >> However, trying to access the metadata for the schema (obtained with >> `garrow_schema_get_metadata`) indicates its size to be 0, which indicates >> that metadata for the schema isn't the same as that for a field. Is it >> possible using the existing API to read/write the metadata for a field? >> >> >> Thank you, >> Ishan
