C Interfaces¶

See also

The C data interface and C stream interface specifications.

ABI Structures¶

struct ArrowSchema¶
struct ArrowArray¶
struct ArrowArrayStream¶

C Data Interface¶

Status ExportType(const DataType &type, struct ArrowSchema *out)¶

Export C++ DataType using the C data interface format.

The root type is considered to have empty name and metadata. If you want the root type to have a name and/or metadata, pass a Field instead.

Parameters:
  • type – [in] DataType object to export

  • out – [out] C struct where to export the datatype

Status ExportField(const Field &field, struct ArrowSchema *out)¶

Export C++ Field using the C data interface format.

Parameters:
  • field – [in] Field object to export

  • out – [out] C struct where to export the field

Status ExportSchema(const Schema &schema, struct ArrowSchema *out)¶

Export C++ Schema using the C data interface format.

Parameters:
  • schema – [in] Schema object to export

  • out – [out] C struct where to export the field

Status ExportArray(const Array &array, struct ArrowArray *out, struct ArrowSchema *out_schema = NULLPTR)¶

Export C++ Array using the C data interface format.

The resulting ArrowArray struct keeps the array data and buffers alive until its release callback is called by the consumer.

Parameters:
  • array – [in] Array object to export

  • out – [out] C struct where to export the array

  • out_schema – [out] optional C struct where to export the array type

Status ExportRecordBatch(const RecordBatch &batch, struct ArrowArray *out, struct ArrowSchema *out_schema = NULLPTR)¶

Export C++ RecordBatch using the C data interface format.

The record batch is exported as if it were a struct array. The resulting ArrowArray struct keeps the record batch data and buffers alive until its release callback is called by the consumer.

Parameters:
  • batch – [in] Record batch to export

  • out – [out] C struct where to export the record batch

  • out_schema – [out] optional C struct where to export the record batch schema

Result<std::shared_ptr<DataType>> ImportType(struct ArrowSchema *schema)¶

Import C++ DataType from the C data interface.

The given ArrowSchema struct is released (as per the C data interface specification), even if this function fails.

Parameters:

schema – [inout] C data interface struct representing the data type

Returns:

Imported type object

Result<std::shared_ptr<Field>> ImportField(struct ArrowSchema *schema)¶

Import C++ Field from the C data interface.

The given ArrowSchema struct is released (as per the C data interface specification), even if this function fails.

Parameters:

schema – [inout] C data interface struct representing the field

Returns:

Imported field object

Result<std::shared_ptr<Schema>> ImportSchema(struct ArrowSchema *schema)¶

Import C++ Schema from the C data interface.

The given ArrowSchema struct is released (as per the C data interface specification), even if this function fails.

Parameters:

schema – [inout] C data interface struct representing the field

Returns:

Imported field object

Result<std::shared_ptr<Array>> ImportArray(struct ArrowArray *array, std::shared_ptr<DataType> type)¶

Import C++ array from the C data interface.

The ArrowArray struct has its contents moved (as per the C data interface specification) to a private object held alive by the resulting array.

Parameters:
  • array – [inout] C data interface struct holding the array data

  • type – [in] type of the imported array

Returns:

Imported array object

Result<std::shared_ptr<Array>> ImportArray(struct ArrowArray *array, struct ArrowSchema *type)¶

Import C++ array and its type from the C data interface.

The ArrowArray struct has its contents moved (as per the C data interface specification) to a private object held alive by the resulting array. The ArrowSchema struct is released, even if this function fails.

Parameters:
  • array – [inout] C data interface struct holding the array data

  • type – [inout] C data interface struct holding the array type

Returns:

Imported array object

Result<std::shared_ptr<RecordBatch>> ImportRecordBatch(struct ArrowArray *array, std::shared_ptr<Schema> schema)¶

Import C++ record batch from the C data interface.

The ArrowArray struct has its contents moved (as per the C data interface specification) to a private object held alive by the resulting record batch.

Parameters:
  • array – [inout] C data interface struct holding the record batch data

  • schema – [in] schema of the imported record batch

Returns:

Imported record batch object

Result<std::shared_ptr<RecordBatch>> ImportRecordBatch(struct ArrowArray *array, struct ArrowSchema *schema)¶

Import C++ record batch and its schema from the C data interface.

The type represented by the ArrowSchema struct must be a struct type array. The ArrowArray struct has its contents moved (as per the C data interface specification) to a private object held alive by the resulting record batch. The ArrowSchema struct is released, even if this function fails.

Parameters:
  • array – [inout] C data interface struct holding the record batch data

  • schema – [inout] C data interface struct holding the record batch schema

Returns:

Imported record batch object

C Stream Interface¶

Status ExportRecordBatchReader(std::shared_ptr<RecordBatchReader> reader, struct ArrowArrayStream *out)¶

Export C++ RecordBatchReader using the C stream interface.

The resulting ArrowArrayStream struct keeps the record batch reader alive until its release callback is called by the consumer.

Parameters:
  • reader – [in] RecordBatchReader object to export

  • out – [out] C struct where to export the stream

Result<std::shared_ptr<RecordBatchReader>> ImportRecordBatchReader(struct ArrowArrayStream *stream)¶

Import C++ RecordBatchReader from the C stream interface.

The ArrowArrayStream struct has its contents moved to a private object held alive by the resulting record batch reader.

Parameters:

stream – [inout] C stream interface struct

Returns:

Imported RecordBatchReader object