How do I write plugins with stable ABIs?

When developing plugins for C++, ensuring a stable ABI (Application Binary Interface) can be quite challenging yet necessary. A stable ABI allows for binary compatibility between different versions of libraries, meaning that plugins can be built against one version of a library and still work with another version of that library. This is crucial for creating a seamless experience for users and preventing issues related to binary incompatibility.

Steps to Write Plugins with Stable ABIs

1. Use a stable C++ standard: Aim to stick to a particular version of the C++ standard that supports your needs and is widely adopted.
2. Minimize use of non-ABI-compliant features: Certain features (like certain classes or templates) can introduce binary compatibility issues.
3. Explicitly define extern "C" for callback functions: This can help ensure that function names remain unchanged across different compilers and compiler versions.
4. Use versioning: Implement versioning in your APIs, helping manage changes over time without breaking existing binaries.
5. Test your plugins against multiple versions: Regularly test your plugins against differing versions of the library they are intended to interact with, to ensure compatibility.

Example of ABI Compatibility in C++ Plugins

extern "C" {
         void my_function(int arg);
     }
     
     void my_function(int arg) {
         // Function implementation
     }