publish_subscribe

Publish-Subscribe

Caution

Every payload you transmit with iceoryx2 must be compatible with shared memory. Specifically, it must:

• be self contained, no heap, no pointers to external sources
• have a uniform memory representation, ensuring that shared structs have the same data layout
• not use pointers to manage their internal structure

This example illustrates a robust publisher-subscriber communication pattern between two separate processes. The publisher sends two messages every second, each containing [TransmissionData]. On the receiving end, the subscriber checks for new data every second.

The subscriber is printing the sample on the console whenever new data arrives.

How to Build

Before proceeding, all dependencies need to be installed. You can find instructions in the C Examples Readme.

First you have to build the C examples:

cmake -S . -B target/ff/cc/build -DBUILD_EXAMPLES=ON -DBUILD_CXX=OFF
cmake --build target/ff/cc/build

How to Run

To observe this dynamic communication in action, open two separate terminals and execute the following commands:

Terminal 1

./target/ff/cc/build/examples/c/publish_subscribe/example_c_publish_subscribe_subscriber

Terminal 2

./target/ff/cc/build/examples/c/publish_subscribe/example_c_publish_subscribe_publisher

Feel free to run multiple instances of publisher or subscriber processes simultaneously to explore how iceoryx2 handles publisher-subscriber communication efficiently.

You may hit the maximum supported number of ports when too many publisher or subscriber processes run. Take a look at the iceoryx2 config to set the limits globally or at the API of the Service builder to set them for a single service.