public int write(
        final int dwCount, // Data count
        final Pointer phServer, // Server handles of items
        final Pointer pItemValues, // Values of items
        final PointerByReference pErrors // Error codes
        ) {
      return this._invokeNativeInt(
          4,
          new Object[] { // Write is the 4th method in vtable
            this.getPointer(), dwCount, phServer, pItemValues, pErrors
          });
    }
We define the OPC DA Classes and interfaces here like C's .h file.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/pipe/connector/protocol/opcda/OpcDaHeader.java