Realtime safety requirements for the logging extension

[robbert-vdh]

The logging extension mentions that the logging callbacks must be callable from any thread: https://github.com/free-audio/clap/blob/main/include/clap/ext/log.h My question is, should the plugin also assume that calling these from a process function is realtime safe? (for as far as logging can be realtime safe) I assume not, but I thought I'd get some clarification first. I was considering how to support the extension in yabridge, and the options are to either a) not support it at all, b) proxy the callbacks as normal (meaning that there will be an allocation for an std::string and a back and forth function call over a a socket, or c) only allocate the string and defer sending the actual callback (would make using these functions from a process function slightly safer, but it still needs to allocate, also a lot more complicated). If there are no realtime safety requirements I'll just keep things simple and go with b).

[abique]

The host should be able to deal with it up to some extents, in worst case the host simply drops the log message.

[abique]

I think it is possible to have some memory available for logging message, but of course this memory isn't infinite, and if the plugin outputs a lot, it'll fill the buffer quickly, maybe quicker than the main thread could pump it due to the scheduler settings.

[abique]

I would not log from the audio thread, unless there is a very important message like critical error message. Because there will always be some host implementing this logging feature in a non real-time way.