How to use Iceoryx for low-level shared memory without middleware?

[leiBravo]

Hello Iceoryx team,

Thank you for your excellent work on Iceoryx! I am currently exploring Iceoryx for inter-process communication and I would like to leverage its low-level shared memory capabilities without using the full middleware stack (e.g., pub/sub).

Could you provide a simple example or guidance on how to use Iceoryx for purely managing shared memory at a low level? Specifically, I am interested in:

• How to create and manage shared memory directly using SharedMemoryObject or other relevant APIs.
• How to perform basic read/write operations between processes using this low-level API.

I have seen examples of Iceoryx's pub/sub architecture, but I am looking for more granular control over shared memory for specific use cases.

Any advice or examples would be greatly appreciated!

Thank you in advance for your help!

[elfenpiff]

@leiBravo Can you tell us a bit more about the use-case you are having? You could, of course, use our low-level building blocks, but maybe the solution to your problem is a feature we will implement in the near future, and this could save you a lot of time.

The construct you are looking for is this here: https://github.com/eclipse-iceoryx/iceoryx/blob/main/iceoryx_hoofs/posix/ipc/include/iox/posix_shared_memory_object.hpp

You can create your own shared memory by calling:

auto shm = PosixSharedMemoryObjectBuilder()
    .name("my_shm_name")
    .memorySizeInBytes(1234)
    .accessMode(AccessMode::READ_WRITE)
    .openMode(OpenMode::OPEN_EXISTING)
    .create()
    .expect("Successful shm creation");

shm.getBaseAddress(); // return void* to the start of the shared memory

But I would recommend not pursuing this. Now, you have to handle all the things we handle within iceoryx:

• deal with resource leaks
• robust concurrent access to shared memory that can survive process crashes
• threadsafe ipc containers

Btw. iceoryx2 comes already with much more advanced features than good old iceoryx - you could also check this out and see if it provides the things you need.