Hello World in C++
Create your first WendyOS application using C++
Creating Your First C++ Application
This guide will walk you through creating a simple "Hello, World!" application for WendyOS using C++. This is a great way to prove that you can send your first app to your device and verify your development environment is set up correctly.
Prerequisites
- Wendy CLI installed on your development machine
- CMake 3.16 or later installed
- A C++ compiler (g++ or clang++)
- A WendyOS device plugged in over USB or connectable over Wi-Fi
Containerized Deployment: C++ applications run inside Docker containers on your WendyOS device. The Dockerfiles in this guide are configured for the NVIDIA Jetson Orin Nano's ARM64 architecture using arm64v8/debian:bookworm-slim as the base image.
Creating the Project
Initialize the Project
Start from the Wendy C++ template:
wendy init hello-world --target wendyos --language cpp --template simple-api --var APP_ID=hello-world --var PORT=7001 --assistant skip --git-init no
cd hello-worldThe template creates CMakeLists.txt, main.cpp, Dockerfile, and wendy.json. Continue below to understand the generated project.
Run on WendyOS
wendy runWendy will build the app, ask you to select a device if one is not already configured, deploy the app, and show the run output.
Code Breakdown
Generated Application
The template includes a main.cpp entry point. A minimal hello-world binary looks like:
#include <iostream>
int main() {
std::cout << "Hello, world!" << std::endl;
return 0;
}This is the entry point for your WendyOS application.
Generated CMakeLists.txt
The generated CMakeLists.txt describes how the project builds:
cmake_minimum_required(VERSION 3.16)
project(hello-world VERSION 0.1.0 LANGUAGES CXX)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
add_executable(hello-world main.cpp)Generated Dockerfile
The generated project includes a Dockerfile configured for the NVIDIA Jetson Orin Nano (ARM64):
# Build stage - using ARM64-compatible image for NVIDIA Jetson Orin Nano
FROM arm64v8/debian:bookworm-slim AS builder
# Install build dependencies
RUN apt-get update && apt-get install -y --no-install-recommends \
build-essential \
cmake \
&& rm -rf /var/lib/apt/lists/*
WORKDIR /app
COPY CMakeLists.txt main.cpp ./
# Build the application
RUN cmake -B build -DCMAKE_BUILD_TYPE=Release && \
cmake --build build --config Release
# Runtime stage
FROM arm64v8/debian:bookworm-slim
COPY --from=builder /app/build/hello-world /usr/local/bin/hello-world
CMD ["hello-world"]Run Again on WendyOS
Deploy your application to a connected WendyOS device:
wendy runThis will build your application into a container and deploy it to your device.
Verifying Deployment on Your Device
After deploying your application to a WendyOS device, you can verify it was successfully deployed and ran by listing the applications on your device:
wendy device apps list
✔︎ Searching for WendyOS devices [5.3s]
✔︎ Listing applications: True Probe [USB, Ethernet, LAN]
╭───────────────┬─────────┬─────────┬──────────╮
│ App │ Version │ State │ Failures │
├───────────────┼─────────┼─────────┼──────────┤
│ hello-world │ 0.0.1 │ Stopped │ 0 │
╰───────────────┴─────────┴─────────┴──────────╯Expected State: The app shows as "Stopped" because a hello-world application exits immediately after printing its message. This is expected behavior. The key indicator of success is the "Failures" column showing 0, which confirms your application ran and exited successfully without any errors.
Next Steps
Now that you have a basic C++ application running:
- Learn how to build a Simple Web Server with cpp-httplib
- Explore environment variables and configuration
- Build more complex applications with networking and data processing
- Integrate with WendyOS device features via HTTP APIs
Containerized Deployment: C++ applications on WendyOS run in containers. This provides isolation and portability, and the Wendy CLI handles the local build setup when deploying to your device.