Getting Started

Welcome to Xronos! This guide will walk you through everything you need to get up and running, from installation to your first working application.

System Requirements

Before you begin, make sure your environment meets the following requirements:

POSIX-compliant OS (Ubuntu 22.04 and 24.04 are tested)
GNU-compliant C++ compiler that supports the C++20 standard
- gcc 11 or later
- clang 16 or later with libstdc++, or clang 20 or later with libc++
CMake 3.28 or later

Hello World

Let’s write your first Xronos application.

Application Code

In a new directory, create a file called hello.cc and paste the following content into it.

#include <iostream>

#include "xronos/sdk.hh"

namespace sdk = xronos::sdk;

class Hello : public sdk::Reactor {
  using sdk::Reactor::Reactor;

  class HelloReaction : public sdk::Reaction<Hello> {
    using sdk::Reaction<Hello>::Reaction;
    Trigger<void> startup_trigger{self().startup(), context()};
    void handler() final { std::cout << "Hello, World!\n"; }
  };

  void assemble() final { add_reaction<HelloReaction>("hello"); }
};

auto main() -> int {
  sdk::Environment env{};
  Hello hello{"hello", env.context()};
  env.execute();
  return 0;
}

CMake Config

Then create CMakeLists.txt. It uses FetchContent to download the pre-built Xronos SDK binary artifacts and links the hello executable against them. For alternative integration methods, see CMake Integration and Installation.

cmake_minimum_required(VERSION 3.28)

project(hello LANGUAGES CXX)

set(XRONOS_SDK_VERSION "0.15.0" CACHE STRING "Xronos SDK version")
include(FetchContent)
FetchContent_Declare(
  "xronos-sdk"
  URL https://github.com/xronos-inc/xronos/releases/download/v${XRONOS_SDK_VERSION}/xronos-sdk-${XRONOS_SDK_VERSION}-Linux-${CMAKE_SYSTEM_PROCESSOR}.tar.gz
)
FetchContent_MakeAvailable(xronos-sdk)
set(xronos-sdk_DIR ${xronos-sdk_SOURCE_DIR}/share/cmake/xronos-sdk)

find_package(xronos-sdk)

add_executable(hello hello.cc)
target_link_libraries(hello xronos::xronos-sdk)

Build and Run

Configure the CMake project and build:

$ cmake -B build
$ cmake --build build --target hello

Then run the application:

$ ./build/hello
Hello, World!

Generate a Diagram

Every Xronos application can be rendered into a diagram that visualizes its reactors, elements, and connections. Here is the diagram for our hello world example.

diagram hello

See Diagram View for instructions on how to generate a diagram view.