4.1.2. Writers¶
Writers is a command that retrieves information of the DataWriters currently active in the network.
4.1.2.1. Key-words¶
These are the key-words recognize as this command:
writer
writers
datawriter
datawriters
publication
publications
w
W
.
4.1.2.2. Arguments¶
Writers command support 0 or 1 argument:
4.1.2.2.1. No argument¶
When no arguments are given to this command, the information shown is a list with every DataWriter currently active in the network, giving their :term:<Guid>, the name of their respective DomainParticipants, and the topic name and topic data type name. The output format is as follows: Simple Writer info.
4.1.2.2.2. Verbose¶
This argument queries for more complete information about each of the DataWriters in the network. It adds information about the QoS. The output got is a list of DataWriters with verbose information. Check the verbose section in order to know which key-words are available for this argument.
4.1.2.2.3. Guid¶
This argument requires a string with Guid format. This command queries the database for a single DataWriter and retrieves its verbose information. This Guid must exist inside the DDS network.
Note
If you are using eProsima Fast DDS Spy as one-shot application, you will need to put GUID in quotes.
4.1.2.3. Output Format¶
The writer information is retrieved in 2 formats depending on the verbose option.
4.1.2.3.1. Simple Writer info¶
guid: <guid>
name: <participant name>
topic: <topic name> [<topic data type name>]
4.1.2.3.2. Verbose Writer info¶
name: <writer name>
guid: <guid>
topic:
- <topic name>
- <topic data type name>
qos:
- durability: <volatile | transient-local>
- reliability: <reliable | best-effort>
4.1.2.4. Example¶
Let’s assume we have a DDS network where 2 ShapesDemo applications are running.
This would be the expected output for the command writers
:
- guid: 01.0f.44.59.21.58.14.d2.00.00.00.00|0.0.1.2
participant: Fast DDS ShapesDemo Participant
topic: Triangle [ShapeType]
- guid: 01.0f.44.59.da.57.de.ec.00.00.00.00|0.0.6.2
participant: Fast DDS ShapesDemo Participant
topic: Circle [ShapeType]
- ...
This would be the expected output for the command writers verbose
:
- guid: 01.0f.44.59.21.58.14.d2.00.00.00.00|0.0.1.2
participant: Fast DDS ShapesDemo Participant
topic:
name: Triangle
type: ShapeType
qos:
durability: volatile
reliability: best-effort
- guid: 01.0f.44.59.da.57.de.ec.00.00.00.00|0.0.6.2
participant: Fast DDS ShapesDemo Participant
topic:
name: Circle
type: ShapeType
qos:
durability: transient-local
reliability: reliable
- ...
This would be the expected output for the command writers 01.0f.44.59.da.57.de.ec.00.00.00.00|0.0.6.2
:
guid: 01.0f.44.59.da.57.de.ec.00.00.00.00|0.0.6.2
participant: Fast DDS ShapesDemo Participant
topic:
name: Circle
type: ShapeType
qos:
durability: transient-local
reliability: reliable