Fusing event loops is always tricky, but if you have the option of exposing individual file descriptors to Racket, then `ffi/unsafe/port` is probably the way to go. You can turn a file descriptor into an event using `unsafe-file-descriptor->semaphore` or `unsafe-fd->evt`, and then you can block on a set using `sync`, etc.
Matthew At Mon, 3 Aug 2020 23:31:20 -0700 (PDT), Robert D Kocisko wrote: > I have an existing c++ app that is entirely event-loop driven with epoll > and I am trying to figure out how to integrate Racket in the same thread > and allow the existing code to work as-is. I have read the docs about the > C api and the FFI but so far a straightforward and clean option is not > apparent to me. The 'embedding' examples that I see appear rather opaque > to me and at best seem to be geared towards an external loop based on > select() rather than epoll(), so I'm assuming that the more straightforward > approach would be to add the existing event handlers onto Racket's event > system. To that end, it seems there should be a way to register the fd's > of interest with Racket and receive a callback when they are read-ready but > I can't see a way to do that. For example, how would I maintain a list of > fds to pass to (sync) if I went that route? Or if it's better to work it > the other way, how would I call (sync) from c code and apply the list of > fds to it? I vaguely can see a way towards it but it seems at best super > inefficient. Any thoughts or suggestions would be greatly appreciated! > > Thanks, > Bob Kocisko > > -- > You received this message because you are subscribed to the Google Groups > "Racket Users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/racket-users/46fb3804-396c-4921-849f-71fe5a6f > ac7ao%40googlegroups.com. -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/racket-users/20200804080838.2d0%40sirmail.smtps.cs.utah.edu.
