18.1.3.4. Publisher

class fastdds.Publisher(*args, **kwargs)

Class Publisher, used to send data to associated subscribers.

begin_coherent_changes()

Signals the beginning of a set of coherent cache changes using the Datawriters attached to the publisher

Return type

ReturnCode_t

Returns

RETCODE_OK if successful, an error code otherwise

copy_from_topic_qos(writer_qos, topic_qos)

Copies TopicQos into the corresponding DataWriterQos

writer_qos topic_qos :rtype: ReturnCode_t :return: RETCODE_OK if successful, an error code otherwise

create_datawriter(*args)

This operation creates a DataWriter. The returned DataWriter will be attached and belongs to the Publisher.

Parameters
  • topic (Topic) – Topic the DataWriter will be listening

  • qos – QoS of the DataWriter.

  • listener (DataWriterListener) – Pointer to the listener (default: nullptr).

  • mask (StatusMask) – StatusMask that holds statuses the listener responds to (default: all).

Return type

DataWriter

Returns

Pointer to the created DataWriter. nullptr if failed.

create_datawriter_with_profile(*args)

This operation creates a DataWriter. The returned DataWriter will be attached and belongs to the Publisher.

Parameters
  • topic (Topic) – Topic the DataWriter will be listening

  • profile_name (string) – DataWriter profile name.

  • listener (DataWriterListener) – Pointer to the listener (default: nullptr).

  • mask (StatusMask) – StatusMask that holds statuses the listener responds to (default: all).

Return type

DataWriter

Returns

Pointer to the created DataWriter. nullptr if failed.

delete_contained_entities()

Deletes all contained DataWriters

Return type

ReturnCode_t

Returns

RETCODE_OK if successful, an error code otherwise

delete_datawriter(writer)

This operation deletes a DataWriter that belongs to the Publisher.

The delete_datawriter operation must be called on the same Publisher object used to create the DataWriter. If delete_datawriter is called on a different Publisher, the operation will have no effect and it will return false.

The deletion of the DataWriter will automatically unregister all instances. Depending on the settings of the WRITER_DATA_LIFECYCLE QosPolicy, the deletion of the DataWriter may also dispose all instances.

Parameters

writer (DataWriter) – DataWriter to delete

Return type

ReturnCode_t

Returns

RETCODE_PRECONDITION_NOT_MET if it does not belong to this Publisher, RETCODE_OK if it is correctly deleted and RETCODE_ERROR otherwise.

enable()

This operation enables the Publisher

Return type

ReturnCode_t

Returns

RETCODE_OK is successfully enabled. RETCODE_PRECONDITION_NOT_MET if the participant creating this Publisher is not enabled.

end_coherent_changes()

Signals the end of a set of coherent cache changes

Return type

ReturnCode_t

Returns

RETCODE_OK if successful, an error code otherwise

get_datawriter_qos_from_profile(profile_name, qos)

Fills the DataWriterQos with the values of the XML profile.

Parameters
  • profile_name (string) – DataWriter profile name.

  • qos (DataWriterQos) – DataWriterQos object where the qos is returned.

Return type

ReturnCode_t

Returns

RETCODE_OK if the profile exists. RETCODE_BAD_PARAMETER otherwise.

get_datawriters(writers)

Fills the given vector with all the datawriters of this publisher.

Parameters

writers (std::vector< eprosima::fastdds::dds::DataWriter *,std::allocator< eprosima::fastdds::dds::DataWriter * > >) – Vector where the DataWriters are returned

Return type

boolean

Returns

true

get_default_datawriter_qos(*args)

Overload 1:

This operation returns the default value of the DataWriter QoS, that is, the QoS policies which will be used for newly created DataWriter entities in the case where the QoS policies are defaulted in the create_datawriter operation.

The values retrieved by get_default_datawriter_qos will match the set of values specified on the last successful call to set_default_datawriter_qos, or else, if the call was never made, the default values.

Return type

DataWriterQos

Returns

Current default WriterQos


Overload 2:

This operation retrieves the default value of the DataWriter QoS, that is, the QoS policies which will be used for newly created DataWriter entities in the case where the QoS policies are defaulted in the create_datawriter operation.

The values retrieved by get_default_datawriter_qos will match the set of values specified on the last successful call to set_default_datawriter_qos, or else, if the call was never made, the default values.

Parameters

qos (DataWriterQos) – Reference to the current default WriterQos.

Return type

ReturnCode_t

Returns

RETCODE_OK

get_instance_handle()

Returns the Publisher’s handle.

Return type

InstanceHandle_t

Returns

InstanceHandle of this Publisher.

get_listener()

Retrieves the attached PublisherListener.

Return type

PublisherListener

Returns

PublisherListener pointer

get_participant()

This operation returns the DomainParticipant to which the Publisher belongs.

Return type

DomainParticipant

Returns

Pointer to the DomainParticipant

get_qos(*args)

Overload 1:

Allows accessing the Publisher Qos.

Return type

PublisherQos

Returns

PublisherQos reference


Overload 2:

Retrieves the Publisher Qos.

Return type

ReturnCode_t

Returns

RETCODE_OK

has_datawriters()

This operation checks if the publisher has DataWriters

Return type

boolean

Returns

true if the publisher has one or several DataWriters, false otherwise

lookup_datawriter(topic_name)

This operation retrieves a previously created DataWriter belonging to the Publisher that is attached to a Topic with a matching topic_name. If no such DataWriter exists, the operation will return nullptr.

If multiple DataWriter attached to the Publisher satisfy this condition, then the operation will return one of them. It is not specified which one.

Parameters

topic_name (string) – Name of the Topic

Return type

DataWriter

Returns

Pointer to a previously created DataWriter associated to a Topic with the requested topic_name

resume_publications()

Indicates to FastDDS that the modifications to the DataWriters are complete.

Return type

ReturnCode_t

Returns

RETCODE_OK if successful, an error code otherwise

set_default_datawriter_qos(qos)

This operation sets a default value of the DataWriter QoS policies which will be used for newly created DataWriter entities in the case where the QoS policies are defaulted in the create_datawriter operation.

This operation will check that the resulting policies are self consistent; if they are not, the operation will have no effect and return false.

The special value DATAWRITER_QOS_DEFAULT may be passed to this operation to indicate that the default QoS should be reset back to the initial values the factory would use, that is the values that would be used if the set_default_datawriter_qos operation had never been called.

Parameters

qos (DataWriterQos) – DataWriterQos to be set

Return type

ReturnCode_t

Returns

RETCODE_INCONSISTENT_POLICY if the Qos is not self consistent and RETCODE_OK if the qos is changed correctly.

set_listener(*args)

Overload 1:

Modifies the PublisherListener, sets the mask to StatusMask::all()

Parameters

listener (PublisherListener) – new value for the PublisherListener

Return type

ReturnCode_t

Returns

RETCODE_OK


Overload 2:

Modifies the PublisherListener.

Parameters
  • listener (PublisherListener) – new value for the PublisherListener

  • mask (StatusMask) – StatusMask that holds statuses the listener responds to

Return type

ReturnCode_t

Returns

RETCODE_OK

set_qos(qos)

Allows modifying the Publisher Qos. The given Qos must be supported by the PublisherQos.

Parameters

qos (PublisherQos) – PublisherQos to be set

Return type

ReturnCode_t

Returns

RETCODE_IMMUTABLE_POLICY if any of the Qos cannot be changed, RETCODE_INCONSISTENT_POLICY if the Qos is not self consistent and RETCODE_OK if the qos is changed correctly.

suspend_publications()

Indicates to FastDDS that the contained DataWriters are about to be modified

Return type

ReturnCode_t

Returns

RETCODE_OK if successful, an error code otherwise

property thisown

The membership flag

wait_for_acknowledgments(max_wait)

This operation blocks the calling thread until either all data written by the reliable DataWriter entities is acknowledged by all matched reliable DataReader entities, or else the duration specified by the max_wait parameter elapses, whichever happens first. A return value of true indicates that all the samples written have been acknowledged by all reliable matched data readers; a return value of false indicates that max_wait elapsed before all the data was acknowledged.

Parameters

max_wait (Duration_t) – Maximum blocking time for this operation

Return type

ReturnCode_t

Returns

RETCODE_TIMEOUT if the function takes more than the maximum blocking time established, RETCODE_OK if the Publisher receives the acknowledgments and RETCODE_ERROR otherwise.