Re: sleep-for documentation and how to pause reliably

[Stefan Monnier <monnier@iro.umontreal.ca>]

>> > However, in fact, sleep-for will return as soon as any input from any
>> > subprocess arrives.
>> That'd be a bug.
> The implementation calls wait_reading_process_output, so I don't see
> how it can behave otherwise, unless it calls that function in a loop
> until the time passes.

I think it should indeed do it in a loop.

> Also, in the meantime I found this in the ELisp manual:
>      Output from a subprocess can arrive only while Emacs is waiting: when
>   reading terminal input (see the function `waiting-for-user-input-p'),
>   in `sit-for' and `sleep-for' (*note Waiting::), and in
>   `accept-process-output' (*note Accepting Output::).  This minimizes the
>   problem of timing errors that usually plague parallel programming.
> So this actually sounds like a deliberate feature.

This doesn't say that it will interrupt sleep-for, only that process
filters will be run during sleep-for.


        Stefan