Function duckdb_append_default_to_chunk 

pub unsafe extern "C" fn duckdb_append_default_to_chunk(
    appender: duckdb_appender,
    chunk: duckdb_data_chunk,
    col: idx_t,
    row: idx_t,
) -> duckdb_state

Append a DEFAULT value, at the specified row and column, (NULL if DEFAULT not available for column) to the chunk created from the specified appender. The default value of the column must be a constant value. Non-deterministic expressions like nextval(‘seq’) or random() are not supported.

@param appender The appender to get the default value from. @param chunk The data chunk to append the default value to. @param col The chunk column index to append the default value to. @param row The chunk row index to append the default value to. @return DuckDBSuccess on success or DuckDBError on failure.