Stop execution of a function

I created a function that prints every sample value from a buffer to the console but it is taking a really long time to execute. I cannot execute ‘s.quit’ or ‘’ for instance because this process is still executing. Is there anyway to just quickly quit a process while executing in the case of an endless loop like you can from unix with most programming languages?

sclang is “non-preemptive,” meaning: once a Thread takes control of the interpreter, it has control until it either finishes, or explicitly yields a value (from a Routine). If it’s a long-running loop without any yields, there’s nothing sclang can do at that point to stop it.

So – this is somewhat irritating but currently necessary – it’s better to write long processes as Routines, with periodic short wait calls. The wait allows opportunities for the interpreter to stop the process. (fork implicitly creates a Routine.)

r = fork { { |i|
        if(i % 1000 == 0) { 0.00001.wait };
        ... do stuff...

// sometime later:

Otherwise, you can do killall sclang in the terminal (not within sclang). The IDE has menu option to stop or reboot the interpreter, you could try that too.


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You can make your function check an external/global stop flag on every big-enough iteration. Such a wrapper exists already as the SkipJack class, to which you pass the “inside-the-loop” function that you want executed repeatedly. The SkipJack takes a stop flag as (extra) input.

This is functionally equivalent to the Routine solution suggested by James, but with Routines you have the extra feature that Ctrl/Cmd+. also stops them, which is probably more suitable in your use case (i.e. CPU hogs). (Yes, you could also make a custom stop flag get set by a CmdPeriod action, as an alternative approach, but Routines basically already encapsulate all this functionality.)