4.1.3. Readers¶
Readers is a command that retrieves information of the DataReaders currently active in the network.
4.1.3.1. Key-words¶
These are the key-words recognize as this command:
reader
readers
datareader
datareaders
subscription
subscriptions
r
R
.
4.1.3.2. Arguments¶
Readers command support 0 or 1 argument:
4.1.3.2.1. No argument¶
When no arguments are given to this command, the information shown is a list with every DataReader currently active in the network, giving their Guid, the name of their respective DomainParticipants, and the topic name and topic data type name. The output format is as follows: Simple Reader info.
4.1.3.2.2. Verbose¶
This argument queries for more complete information about each of the DataReaders in the network. It adds information about the QoS. The output got is a list of DataReaders with verbose information. Check the verbose section in order to know which key-words are available for this argument.
4.1.3.2.3. Guid¶
This argument requires a string with Guid format. This command queries the database for a single DataReader 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.
4.1.3.3. Output Format¶
The reader information is retrieved in 2 formats depending on the verbose option.
4.1.3.3.1. Simple Reader info¶
guid: <guid>
name: <participant name>
topic: <topic name> [<topic data type name>]
4.1.3.3.2. Verbose Reader info¶
name: <reader name>
guid: <guid>
topic:
- <topic name>
- <topic data type name>
qos:
- durability: <volatile | transient-local>
- reliability: <reliable | best-effort>
4.1.3.4. Example¶
Let’s assume we have a DDS network where 2 ShapesDemo applications are running.
This would be the expected output for the command readers
:
- 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 readers 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 readers 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