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It looks like it could; the timer isn't the problem (they're just entries in a queue), but #'shell-command-to-string call might be. It's a synchronous, blocking call (at least on my Emacs 26, running (shell-command-to-string "sleep 5") hangs the whole Emacs nicely for 5 seconds). Personally, I'd reimplement it the way you suggest - I'd put the timer loop in C code to save on repeatedly starting a process, and then make it run emacsclient -e "(change-theme-for-lighting %d)", where %d is a sensor value, whenever that value crosses a threshold. Alternatively, if you want to keep the entire business logic within Emacs Lisp code, there's some way to make it work too. I'd look into documentation of #'make-process[0]. There's an argument :FILTER that would let you set a function that receives stdout from that process. Alternatively, #'start-process-shell-command with NIL for buffer, + #'set-process-filter should achieve the same thing. So the C program would be barfing out the sensor value every second or so, and the process filter would read it. (You might also want to read through the sources of #'shell-command to see how it uses the above facilities to handle asynchronous shell processes - the ones you invoke with M-x async-shell-command - but I think it'll work out of the box, and the process filter will only be executed as new output arrives.) -- [0] - in Emacs, type: C-h f make-process. Gotta love the self-documenting features of this editor. Actually, half of my comment is based on what I just read in docs of various Emacs functions. Also, hint: make sure you install Emacs with sources - then you can easily jump from help buffer directly into code implementing the thing you're reading about. |