On 10/2/2021 7:25 PM, Don Green wrote:
Looking to trigger the end of a loop by the creation of a file.
Is this possible? Is this advisable?
Currently using:
a 'for' loop with
a 'for' loop guard expression to test for the existence of a file.
Tried file-exists? but that does not seem appropriate.
Tried using Racket function: filesystem-change-evt but that did not seem appropriate. Is it possible to trigger an end condition on a 'for' loop by the creation of a file? I suspect my problem is that it takes a significant amount of time for the operating system to register the creation of a file. So maybe the best that can be done is to use file-exists? as it works but there a many loops of the 'for' loop before the end condition takes effect.
Any comments? --

Is the loop doing something else while it waits?  If not, you might as well use  filesystem-change-evt.

A polling loop /may/ respond faster than waiting on an event, but at the level of user applications that is /not/ guaranteed.  Is there some reason you (think you) need to respond very quickly when the file is created?

George

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