[#390] Add readme

examples/cxx/event_based_communication/README.md

@@ -1 +1,35 @@
-# asd
+# Event-Based Communication
+
+## Running The Example
+
+This example demonstrates iceoryx2's event multiplexing mechanism in a more
+complex setup. The iceoryx2 `Publisher` and `Subscriber` are integrated into
+custom `ExamplePublisher` and `ExampleSubscriber` classes, which also
+incorporate an additional iceoryx2 `Notifier` and `Listener`. This setup
+enables automatic event emission whenever an `ExamplePublisher` or
+`ExampleSubscriber` is created or dropped. Additionally, events are emitted
+whenever a new `Sample` is sent or received.
+
+When a `class` inherits from `FileDescriptorBased`, it can be attached to a
+`WaitSet`. Both `ExamplePublisher` and `ExampleSubscriber` implement this
+interface by forwarding calls to their underlying `Listener`, which already
+provides an implementation of `FileDescriptorBased`.
+
+The `WaitSet` notifies the user of the origin of an event notification. The
+user can then acquire the `EventId` from the `Listener`. Based on the value of
+the `EventId`, the user can identify the specific event that occurred and take
+appropriate action.
+
+### Terminal 1
+
+```sh
+./target/ffi/build/examples/cxx/event_based_communication/example_cxx_event_based_communication_publisher
+```
+
+### Terminal 2
+
+```sh
+./target/ffi/build/examples/cxx/event_based_communication/example_cxx_event_based_communication_subscriber
+```
+
+Feel free to run multiple publishers or subscribers in parallel.

examples/cxx/event_based_communication/src/pubsub_event.hpp

@@ -31,12 +31,12 @@ enum class PubSubEvent : uint8_t {
 
 namespace iox {
 template <>
-inline constexpr auto from<PubSubEvent, size_t>(const PubSubEvent value) noexcept -> size_t {
+constexpr auto from<PubSubEvent, size_t>(const PubSubEvent value) noexcept -> size_t {
     return static_cast<uint8_t>(value);
 }
 
 template <>
-inline constexpr auto from<size_t, PubSubEvent>(const size_t value) noexcept -> PubSubEvent {
+constexpr auto from<size_t, PubSubEvent>(const size_t value) noexcept -> PubSubEvent {
     switch (value) {
     case from<PubSubEvent, size_t>(PubSubEvent::PublisherConnected):
         return PubSubEvent::PublisherConnected;