Beefy Boxes and Bandwidth Generously Provided by pair Networks DiBona
Keep It Simple, Stupid
 
PerlMonks  

Re^2: Perl Best Practices book: is this one a best practice or a dodgy practice?

by eyepopslikeamosquito (Canon)
on Sep 03, 2005 at 06:47 UTC ( #488869=note: print w/ replies, xml ) Need Help??


in reply to Re: Perl Best Practices book: is this one a best practice or a dodgy practice?
in thread Perl Best Practices book: is this one a best practice or a dodgy practice?

Well, if the suggested idiom doesn't work under Windows, I'd argue that either Windows (or possibly Perl) is broken in that regard.

Good luck getting Bill Gates or p5p to acknowledge that their unlink is broken. ;-) The Perl documentation for the unlink function is annoyingly vague: "Deletes a list of files. Returns the number of files successfully deleted.".

The POSIX unlink semantics are clearer, if difficult to implement on non Unix systems, as noted in djgpp POSIX unlink specification:

The POSIX specification requires this removal to be delayed until the file is no longer open. Due to problems with the underlying operating systems, this implementation of unlink does not fully comply with the specs; if the file you want to unlink is open, you're asking for trouble -- how much trouble depends on the underlying OS.

I might add that the ANSI C remove function does not appear to mandate POSIX semantics: calling remove on an open file on Linux works (a la POSIX unlink), while on Windows it fails.

BTW, I found a related discussion of atomic file update in the "Atomic in-place edit" section in This Week on perl5-porters (18-24 November 2002). Not sure if anything was resolved, however. (Update: apart from MJD submitting a Bug report for the Universe :-).


Comment on Re^2: Perl Best Practices book: is this one a best practice or a dodgy practice?
Select or Download Code

Log In?
Username:
Password:

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://488869]
help
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others making s'mores by the fire in the courtyard of the Monastery: (12)
As of 2014-04-18 06:04 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    April first is:







    Results (462 votes), past polls