This document discusses different architectures for inter-thread communication (ITC) in automotive software projects. It compares approaches based on an event loop model versus using CommonAPI. The event loop model involves each component (HMI, CTRL, SDK) running on its own thread with no direct communication. CommonAPI provides an interface definition language and code generation to define and implement interfaces between components across threads. While the event loop is simpler, it risks blocking and depends on the programming language. CommonAPI standardizes IPC, supports multiple languages, and avoids runtime impacts, though it increases build time and complexity. In conclusion, CommonAPI provides a common solution for IPC and ITC that works across languages, but is

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Yevhen Beshkarov
C++ developer
Difference in
Architecture Based
on Event Loop and
CommonAPI

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General architecture of the majority the automotive projects
HMI
CTRL
SDK
HMI(Human machine interface) - this is our View.
The original source of all events associated with the
user.
CTRL(Controller) - this is our business logic. The
decision about what to do with the information coming
from the user and the SDK we accept on the
controller.
SDK - the lowest level of our architecture. Performs
many tasks to build a route, search, render, etc.

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The problem of communication
HMI
CTRL
SDK
Each component have own thread and there is no
way to get a pointer for a direct call. And if it does, it
will not be very safe.
What to do ???

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ITC on Event Loop

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CommonAPI
● Create a FrancaIDL file with the specification of an interface with methods and attributes.
● Generate code for client and service by starting the CommonAPI code generator.
● Implement the service by implementing the methods in the generated skeleton.
● Implement the client by creating proxies and calling these methods by using the proxy.

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ITC on CommonAPI

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Event Loop vs CommonAPI
➕ Simplicity
➖ Blocking
➖ Depends on the programming language
➕ Just implement IPC
➕ With fidl we can generate interfaces on
different programming languages
➕ Doesn't affect on runtime
➖ Increases building time
➖ Difficult configurable

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So what is the actual difference
• CommonAPI is the common solution for IPC and ITC communication
• CommonAPI can generate his interfaces on different programming languages
• CommonAPI rather cumbersome

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Questions