[C# C++] passing RecordBatch or Table from C++ build DLL to C#

[Bjoern Bachmann]

Hello Arrow users,

I would need some help to understand how I can pass an RecordBatch or a table created in a C++ build DLL into a C# application? How could this be handled efficiently without much data copies?


 

Kind Regards,
Bjoern Bachmann.

 

C++ sample code which is exported in the DLL:

 

std::queue<std::shared_ptr<arrow::RecordBatch>> wfmQueue;

 


ARROW_EXAM_API long EnqueueWaveformChunks()
    {

        //En-Queue Loop
        std::cout << "En-Queue Data ... \n";
        for (int i = 0; i < chunk_size; i++) {
            createWfmSrc(col0_data, col1_data);
            WaveformChunkWriterHelper testWfm{ col0_data, col1_data };  //creates schema and adds the data
            testWfm.createRecBatch();
            wfmQueue.push(testWfm.getRecBatch());
        }
        return S_OK;
    }

 

    ARROW_EXAM_API long DequeueSingleWaveformChunk(arrow::RecordBatch* recBatch)
    {
        std::shared_ptr<arrow::RecordBatch> queueItem;
        if (!wfmQueue.empty()) {
            queueItem = wfmQueue.front();
            wfmQueue.pop();

            std::cout << "Get RecBatch from Queue\n";
      
            recBatch = queueItem.get();

            //ExportRecordBatch(*queueItem, c_array);
            //recBatch = reinterpret_cast<void*>(queueItem.get());
        }
        return S_OK;
    }