Re^2: File lock demo

Hi Dave

I finally found the 45 min to watch the video. :)

I've actually been at this conference, pity I missed your talk.

I just wanted to add for the records that unfortunately your advise that

"you can unlink an open filehandle"

is not universally true. :/

This fails on Win:

> perl
print my $file="random".rand(1000); 
open my $fh,">",$file or die $!; 
unlink ($file) or die $!
__END__
Permission denied at - line 1.
random741.284161646949
[download]

The same code runs without issues on linux

Thanks again! :)

Cheers Rolf
_{(addicted to the Perl Programming Language :)

Wikisyntax for the Monastery}

Comment on Re^2: File lock demo Download Code

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Re^3: File lock demo by davido (Cardinal) on Apr 24, 2021 at 17:27 UTC
Thanks, that's good information. And how unfortunate, too. Every OS has its warts. I guess I'm happy with the devil I know (Linux). Dave	[reply]
Re^4: File lock demo by LanX (Sage) on Apr 24, 2021 at 17:38 UTC
> And how unfortunate, too. Thankfully I don't have the requirement for an "atomic deletion" of the file, because I'm locking a semaphore file the target files have unique names their content is not security relevant it's basically logging for observing state and retrieving errors But I'm trying to build my solution as OS agnostic as possible. I will let you know if I find something for "atomic deletion" on Win.° update °) though a use case might help to wrap my head around it. And Win has symlinks now... > I guess I'm happy with the devil I know (Linux). I still rather feel like a Linuxer even after 5 years in a Win project. Cheers Rolf _{(addicted to the Perl Programming Language :) Wikisyntax for the Monastery}	[reply]
Re^3: File lock demo by eyepopslikeamosquito (Bishop) on Apr 24, 2021 at 22:06 UTC
This reminds me of a long battle I had with The Damian, where he finally acknowledged he made a boo boo in Perl Best Practices, due to his lack of knowledge of differences in behaviour of Perl's `unlink` function between Unix and Windows: Perl Best Practices book: is this one a best practice or a dodgy practice? Re-runnably editing a file in place (see also this related atomic rename node) I'm pretty sure that's the only argument I ever won against him. :)	[reply] [d/l]
Re^4: File lock demo by LanX (Sage) on Apr 24, 2021 at 23:45 UTC
> This reminds me of a long battle I had with The Damian, For the records, no battle here. Davido only mentioned this after being asked, that was not part of any slides. :) > he made a boo boo FWIW I always thought that documentation should have a test suite too. At least the perldocs. Cheers Rolf _{(addicted to the Perl Programming Language :) Wikisyntax for the Monastery}	[reply]


good chemistry is complicated, and a little bit messy -LW
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Re^2: File lock demo

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