Re: [LAD] Realtime inter-thread communication

Hello fellow audio developers, I've started writing a software synthesizer in C++ (using SDL2 for now) for kicks and giggles and ran into the problem of having the event loop thread that listens for keyboard events communicate with the audio callback. Are there any recommendations for how to pass real-time events (note on, note off, etc) to such an audio callback? I figured, this is already a solved problem and that I could benefit from your experiences. Maybe you know of some nice open-source C++ queue implementation that is suitable in such a situation. I could use some kind of "channel" (thread-safe bounded buffer implemented using mutexes and condition variables) but I'm not sure whether this is a good idea in this situation since the audio callback function should avoid unnecessary delays.

I've also looked into LV2. If I implemented the synthesizer as LV2 plugin, I would get around having to solve the inter-thread communication problem because it's the plugin host's responsibility. But to be honest I've found this API to be a bit intimidating and I'm not familiar with any LV2 host that would allow me to test such a plugin. Any recommendations? Ardour?