Re: Easy way to check if a file is open needed.

Why do you need it? Most processes don't care about the name of a file they've already opened. The filehandle stays connected to it even if the file name changes:

#!/usr/bin/perl
use warnings;
use strict;
use feature qw{ say };

open my $OUT, '>', '1' or die $!;

my $child = fork;
if ($child) {
    sleep 1;
    my %new_name = map +($_ => $_ + 1), 1 .. 8;
    for my $old (1 .. 8) {
        rename $old, $new_name{$old} or die $!;
        say "$old renamed to $new_name{$old}.";
        sleep 1;
    }
    exit
}

defined $child or die "Can't fork";
for (1 .. 10) {
    say {$OUT} $_;
    say "Printed: $_.";
    sleep 1;
}
[download]

map{substr$_->[0],$_->[1]||0,1}[\*||{},3],[[]],[ref qr-1,-,-1],[{}],[sub{}^*ARGV,3]

Comment on Re: Easy way to check if a file is open needed. Select or Download Code

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Re^2: Easy way to check if a file is open needed. -- MSWin32 by Discipulus (Canon) on Apr 09, 2019 at 07:06 UTC
Hello choroba, when I read > The filehandle stays connected to it even if the file name changes I said: oh what good news! But when I tried it appears to behaves differently on MSWin32: I suddendly get `Permission denied at writetorenamed.pl line 13.` after had printed 1 or 2 and the file get not renamed ;( `perl writetorenamed.pl Printed: 1. Printed: 2. Permission denied at writetorenamed.pl line 13. Printed: 3. Printed: 4. Printed: 5. Printed: 6. Printed: 7. Printed: 8. Printed: 9. Printed: 10. cat 1 1 2 3 4 5 6 7 8 9 10` [download] L* There are no rules, there are no thumbs.. Reinvent the wheel, then learn The Wheel; may be one day you reinvent one of THE WHEELS.	[reply] [d/l] [select]
Re^3: Easy way to check if a file is open needed. -- MSWin32 by choroba (Cardinal) on Apr 09, 2019 at 07:35 UTC
Yes, my comment is valid only for nix and macOS. `map{substr$_->[0],$_->[1]\|\|0,1}[\\|\|{},3],[[]],[ref qr-1,-,-1],[{}],[sub{}^*ARGV,3]`	[reply] [d/l]
Re^2: Easy way to check if a file is open needed. by Apt_Addiction (Novice) on Apr 09, 2019 at 09:22 UTC
Thank you for your reply. It's taken me a while to reply to this because I can't work out what a fair bit of it's doing! I've not come across map before, so I'll have a look at this today and learn. Why do I need it? It's just so that a file that's open in MS Word, for example, doesn't get renamed.	[reply]