publish_subscribe_with_user_header

Publish-Subscribe With User Header

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

Running The Example

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

Data types like std::string or std::vector will cause undefined behavior and may result in segmentation faults. We provide alternative data types that are compatible with shared memory. See the complex data type example for guidance on how to use them.

This example illustrates a publisher-subscriber communication pattern between two separate processes with an additional user header, referred to as a CustomHeader. The publisher sends messages every second, each containing an incrementing number and the CustomHeader, which includes an additional version number and a timestamp. On the receiving end, the subscriber checks for new data every second and prints out the received payload and the user header.

First you have to build the C++ examples:

cmake -S . -B target/ffi/build -DBUILD_EXAMPLES=ON
cmake --build target/ffi/build

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

Terminal 1

./target/ffi/build/examples/cxx/publish_subscribe_with_user_header/example_cxx_publish_subscribe_user_header_subscriber

Terminal 2

./target/ffi/build/examples/cxx/publish_subscribe_with_user_header/example_cxx_publish_subscribe_user_header_publisher

Feel free to run multiple instances of the 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 are running. Check the iceoryx2 config to set the limits globally or refer to the API of the Service builder to set them for a single service.