MAVLink C++ UDP Example

The MAVLink C++ UDP Example is a simple C++ 11 example that sends and receives MAVLink HEARTBEATs over UDP.

It is the C++ 11 counterpart to the C UDP example: instead of the C pack/decode functions, it uses the generated message structs (e.g. mavlink::minimal::msg::HEARTBEAT) together with mavlink::MsgMap to serialize and deserialize to and from a mavlink_message_t.

INFO

The example should work on any Unix-like system (Linux, MacOS, BSD, etc.). These instructions were tested on a Ubuntu LTS 22.04 installation with either PX4 or ArduPilot dependencies installed (such as cmake).

WARNING

The C++ 11 library requires you to provide a mavlink::mavlink_get_msg_entry() function so that mavlink_parse_char() can look up the length and CRC extra of incoming messages. This example builds it from the dialect's MESSAGE_ENTRIES table (see the top of udp_example.cpp, and the Parsing Packets section for more detail).

Building/Running the Example

The following instructions show how to build and run the example.

1. Clone the mavlink/mavlink repository

2. Open a terminal in the repository root.

3. Use cmake to install MAVLink locally:

   cmake -Bbuild -H. -DCMAKE_INSTALL_PREFIX=install
   cmake --build build --target install

   This installs both the C (*.h) and C++ 11 (*.hpp) headers.

4. Navigate to examples/cpp

   cd examples/cpp

5. Use cmake to compile and build the example:

   cmake -Bbuild -H. -DCMAKE_PREFIX_PATH=$(pwd)/../../install
   cmake --build build

6. Run the executable from the terminal:

   ./build/udp_example

   By default, the example will listen for data on the localhost IP address, port 14550.

7. Open another terminal on the same machine and start either PX4 or ArduPilot. These publish to port 14550 on localhost by default.

8. The example should start displaying messages about sent and received HEARTBEAT messages in the terminal. The following output is displayed if you connect to PX4:

   ~/github/mavlink/mavlink/examples/cpp$  ./build/udp_example
   
   Sent heartbeat
   Got heartbeat from PX4 autopilot
   Sent heartbeat
   Got heartbeat from PX4 autopilot
   Sent heartbeat
   Got heartbeat from PX4 autopilot
   Sent heartbeat
   Got heartbeat from PX4 autopilot
   Sent heartbeat
   Got heartbeat from PX4 autopilot
   ...

Note that the build and installation instructions are from examples/cpp/README.md.