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# holoscan::dds_qos::apply_reader_qos

> Map a GXF QoSProfile struct to FastDDS DataReaderQos.

```cpp showLineNumbers={false}
void holoscan::dds_qos::apply_reader_qos(
    eprosima::fastdds::dds::DataReaderQos &dds_qos,
    const nvidia::gxf::QoSProfile &qos
)
```

[Map](../../../classes/map) a GXF QoSProfile struct to FastDDS DataReaderQos.

Maps the same fields as apply\_writer\_qos(), except:

* lifespan is not applicable to readers (DDS spec)
* max\_blocking\_time is not applicable to readers (writer-side only)
* transport\_priority is not applicable to readers

**Parameters**

The DataReaderQos to configure (modified in-place). Must be freshly default-initialized (e.g. `DATAREADER_QOS_DEFAULT`). Reusing a previously configured object may leave stale values.

The GXF QoSProfile to map from.

**See also:**
docs/PUBSUB\_DESIGN/DDS\_BACKEND\_ADOPT\_NEW\_GXF\_APIS.md §3