DataWriter

22 posts / 0 new
Last post
His Nerdship's picture
Offline
Last seen: 3 weeks 3 days ago
Joined: 05/08/2019
Posts: 18
Check if a DataWriter is ready to write

Following on from my previous post re unreliable WiFi connections, I found that the problem was caused by calling DataWriter::write()too soon after creating the DataWriter.  Because write()is non-blocking it returned immediately without doing anything.  Also, because it is void, there is no error return code.

So the publishing app was not in fact sending anything, and I had no way of knowing.

It obviously needed more time to assemble its plumbing, so I put in a 2 second sleep, after which it worked.

Organization:
3 posts / 0 new
Last post
Offline
Last seen: 2 months 3 weeks ago
Joined: 09/06/2018
Posts: 22
sending only fields that have changed

Hi,

 

We are using RHEL7.5 and RTI DDS 5.3.1.

I've done some searching already.  I was wondering if it was possible for a datawriter to only send the fields that have changed in a message and a datareader to only act on those 'changed' fields.  Am I correct that this feature does not exist in RTI DDS currently?

2 posts / 0 new
Last post
Offline
Last seen: 9 months 13 hours ago
Joined: 03/25/2018
Posts: 10
Can we dynamically create and free data writer?

Hi,

Currently, all data writers are created before use and that consumes memory. Some topics (and thus data writers) are events that only be invoked under certain scenarios, and can be created when necessary and release after used.

Is there a way to support dynamic creation and release of data writers, just like malloc() and free() ?

Organization:
5 posts / 0 new
Last post
Offline
Last seen: 6 months 5 days ago
Joined: 10/14/2018
Posts: 5
DataWriter pause problem

Hello ~
We are using version 5.2.2 of DDS.
We have delivered the program using DDS.
But when the customer tells us that our program is kill process
The customer's DataWriter pauses and then resends after a few seconds.
We think this is due to the Qos configuration, but we are not sure.
Could you give me some advice on this situation?

Keywords:
3 posts / 0 new
Last post
Offline
Last seen: 2 years 2 weeks ago
Joined: 03/03/2015
Posts: 19
DataWriter callback when writer queue is available for writing

Hey,

I'm have a DDS_DataWriter configured to keep history with a depth of 128. After 128 written samples, the DDS_DataWriter returns a "DDS_RETCODE_TIMEOUT" error, which is expected because the buffer is full and no DDS_DataReader has read anything from it.

Organization:
2 posts / 0 new
Last post
Offline
Last seen: 3 weeks 3 days ago
Joined: 12/07/2016
Posts: 10
Multiple threads publishing on the same topic

Hello:

I'm developing a multithreaded application which publishes data on a DDS topic using write. My questions about this method are this:

Organization:
9 posts / 0 new
Last post
Offline
Last seen: 2 years 11 months ago
Joined: 07/26/2016
Posts: 6
Writer error

Hi,

 

I get the error below when trying to write -   Writer.write(instance, ref instance_handle);

What is the problem?

7 posts / 0 new
Last post
Offline
Last seen: 4 years 6 months ago
Joined: 05/25/2014
Posts: 6
How to publish fixed payload size data ? + casting 'DDS.StringDataWriter' to 'DDS.BytesDataWriter' ERROR !

Hello Everybody,

I have two questions + I need code troubleshooting.  

1# How I can send fixed payload size using data writer with certain publishing rate to mimic sensor behavior? 

2# Is it possible to send different string using StringDataWriter with the same payload (string) size all the time? 

 

ERROR:

I used DynamicDataWriter or BytesDataWriter but I always get error here:

Keywords:
Subscribe to RSS - DataWriter