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Re^11: true from (-e "") on Windoze (" is an illegal filename character

by syphilis (Canon)
on Sep 20, 2012 at 01:58 UTC ( #994574=note: print w/ replies, xml ) Need Help??


in reply to Re^10: true from (-e "") on Windoze (" is an illegal filename character
in thread true from (-e "") on Windoze

I need a function that checks if file exists

Seems to me that (on Windows) we can be assured that the specified $file exists if any one of the following three conditions returns true:

-T $file || -B $file defined -T $file defined -B $file
I was also wondering about using -f instead of -e. Are there any files on Windows that will report false for -f ? (If so, then we can't use -f as a test for existence.)

Someone really ought to file a bug report about this because the perldoc -f -X documentation does *not* match the behaviour wrt '-e'.
That documentation implies that -e '""' will return true only if a file named "" exists.
Either the behaviour ought to change to fit the documentation, or the documentation be amended to fit the behaviour.
The documentation also implies that defined -f '""' will return false (but it doesn't).
Here's what I ran as a check:
#!perl -l use warnings; print "-f:"; -f '""' ? print "Returned True (unwanted behaviour)\n" : print "Returned False (wanted behaviour)\n"; print "defined -f:"; defined -f '""' ? print "Returned True (unwanted behaviour)\n" : print "Returned False (wanted behaviour)\n"; print "-T || -B:"; (-T '""' || -B '""') ? print "Returned True (unwanted behaviour)\n" : print "Returned False (wanted behaviour)\n"; print "defined -T:"; defined -T '""' ? print "Returned True (unwanted behaviour)\n" : print "Returned False (wanted behaviour)\n"; print "defined -B:"; defined -B '""' ? print "Returned True (unwanted behaviour)\n" : print "Returned False (wanted behaviour)\n";
And here's the output I got:
-f: Returned False (wanted behaviour) defined -f: Returned True (unwanted behaviour) -T || -B: Returned False (wanted behaviour) defined -T: Returned False (wanted behaviour) defined -B: Returned False (wanted behaviour)
I don't mind filing a bug report about this, but I'll wait for comments about that first (in case I've overlooked something).

Cheers,
Rob


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