AutoHotkey Community

To me, the (#persistent) command is quite mysterious. I hardly
know what it is for and the example in the "Help" file doesn't
explain anything.

The "Help" file page on #persistent says:

"If this directive is present anywhere in the script, that script will
stay running after the auto-execute section (top part of the script)
completes. "

Does that mean that my script below #persistent will be running
again, again and again like a loop?

Another thing that kind of scares me is this (from the same page
of the "Help" file):

"If this directive is added to an existing script, you might want to
change some or all occurrences of Exit to be ExitApp. This is
because Exit will not terminate a persistent script; it terminates
only the current thread."

Well, if it's only about changing Exits to ExitApps, then I can go
with it, but can it happen so that #persistent will damage or
influence somehow some other portions of script?

Why does the following script work similarly both with and
without the #persistent command in the first line?

The #persistent command force the script to stay in memory in the exact same way your hotkey make it stay in memory.

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No, it means scripts having no hotkeys, hotstrings, Onmessage() or Gui will not terminate after the auto-execute section completes.


Consider the following example which incorporates the usefulness of using #Persistent:


If you comment out the first line you'll notice that the script reaches Return line at the end of the auto-execute section before the timer has had a single chance to run. Because there are no hotkeys, hotstrings, Onmessage() or Gui there's nothing to keep the script running which means the script will terminate the moment it has reached and processed the aforementioned Return line. The purpose of #Persistent is to prevent that from happening.


That's because you've got hotkey definitions in the script. Those definitions basically prevent the script from terminating at the end of the auto-execution. Meaning you won't benefit from using #Persistent in this case.

thank you for the explanation, Kellianjaxon
also an example , needs persistent

As Kellianjaxon hinted, it is necessary to understand what the Auto-execute Section is, to grasp the meaning of #Persistent. The first two paragraphs are most relevant.In my experience, the only useful purpose of #Persistent is to keep a timer running. If SetTimer was added to the list of commands that automatically make a script persistent, I think the directive could be eliminated entirely.

Kellianjaxon, thank you very much for very clear explanation and for the vivid example!!!

I see, jaco0646, thank you. You're right, Auto-Execute section was something I didn't understand either.