This is a complete message bus implementation https://codeberg.org/maandree/bus Perhaps it can be reused? Or at least mentioned under "Similar work" here https://skarnet.org/software/skabus/
I wouldn't say "complete", because depending on your definition of "bus"
it's unfortunately not possible to implement one without a daemon on Unix - but yeah it's doing pubsub, similarly to s6's libftrig (but more efficiently via shmem). Added to the skabus "similar work" section, thanks for mentioning it! -- Laurent
