What all can trigger `async mode`?

[guygastineau]

I found mention of async mode getting triggered by festival_say_file here, and this requires calling festival_wait_for_spooler. I have some minimal bindings to festival for haskell, and I think I will publish the first release sometime in February. I hope to avoid async mode for simplicity, and I am not sure it will play well with the threaded runtime most haskellers are using. Of course we can run the festival library stuff in it's own posix thread (and I plan to do that for some things), but I would like to make the API surface simple, and any such caveats should be codified at the type level or left out entirely. Therefore, I am hoping to find a list of functions which trigger this async mode. Is there such a list? Can async mode get triggered by SIOD code executed by festival?

Thank you for taking the time to engage with my queries!

[orowith2os]

I am also interested, the random bit of "async" confused me on how to manage some Rust bindings.