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.


sending only fields that have changed



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?

Can we dynamically create and free data writer?


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() ?


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?


DataWriter callback when writer queue is available for writing


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.


Multiple threads publishing on the same topic


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


Writer error



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

What is the problem?

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? 



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

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