After I build the generator, I want to make it available on my system so CMake can find it with find_program(microxrceddsgen REQUIRED), or I can use the CLI from anywhere without having to find the path to microxrceddsgen

What do you think adding a section just after install to make the binary available on PATH so you can call the generator from anywhere, or use it in other build systems?

In FastDDSGen, it already has a note on it here.

I propose to be more explicit

Add this to ~/.bashrc to make microxrceddsgen available for use anywhere on your system. Customize the path to where 

export PATH=$PATH:/your/path/to/Micro-XRCE-DDS-Gen/scripts

Another approach would be to set up some sort of install task for the gradle build to install the binary in system headers.
https://docs.gradle.org/current/samples/sample_building_cpp_applications.html#build_the_application

I'm not familiar with Gradle, but maybe that's another approach.

It's not clear what the error codes are used in the custom transport.

size_t my_custom_transport_read(
        uxrCustomTransport* transport,
        uint8_t* buffer,
        size_t length,
        int timeout,
        uint8_t* errcode)
{
    ...
}

The error code is a pointer to a uint8_t. In ArduPilot, which is based on ChibiOS, we have written a custom transport adapter here, which passes error codes from LWIP to MicroXRCEDDS like so:
https://github.com/ArduPilot/ardupilot/blob/c54529aaf850390f7cc3d1583541e0055fc4c7ad/libraries/AP_DDS/AP_DDS_UDP.cpp#L65

The trouble is, what are the actual error codes used by MicroXRCEDDSGen?

I would much prefer if this was exposed as an enum so we could tell whether the codes were matched up, or at least documented what the supported codes are.

The result of this is a long-standing bug in ArduPilot - UDP transport doesn't work ChibiOS:
ArduPilot/ardupilot#25784

Should we expect a code 11 to result in MicroXRCEDDSAgent trying a read/write at a later time and not to drop the data?

The installation refers to

git submodules init
git submodules update

Shouldn't that be

git submodule init
git submodule update

Hi, I am a new hand who has read the specification of XRCE-DDS, and I have some problems with the sessionID and the client_key.
In the specification clause 7.8.2.1, we said we will

Check if there is an existing XRCE ProxyClient object associated with the same client_key and, if so, compare the session_id of the existing ProxyClient with the one in the client_representation:

• If a ProxyClient exists and has the same session_id, then the operation shall not perform any action and shall set the returnValue StatusValue to STATUS_OK.
• If a ProxyClient exists and has a different session_id then the operation shall delete the existing XRCE ProxyClient object and subsequently take the same actions as if there had not been a ProxyClient associated with the client_key.

And there are two clients in the deployment example, the first one is the configurator client and the second one is Publisher. They have the same client_key(0xAABBCCDD), so do they have the same sessionId when they connect to the agent? If they don't, should the Agent delete the ProxyClient and create a new one? After that, can the Publisher publish messages successfully? If they do, how to understand

The sessionId is unique to an XRCE Agent for a given XRCE Client.

in clause 8.3.2.1 of the specification?

Please help me! Thank you very much!

Best regards