Re^4: threads::shared - when to lock a hash ?

The ops never return junk; they will return values consistent with whatever thread did the most recent update. For example, this will never die:

use threads;
use threads::shared;
my $x : shared;

for (0..9) {
    threads->new(sub { 
            while (1) {
            $x = $_[0];
            die unless $x =~ /^\d$/;
            }
        },
        $_
    );
}
sleep;
[download]

There is one iterator per shared object, which is why I mentioned earlier that if other threads do each/keys/value too, it will affect the result

Dave.

Comment on Re^4: threads::shared - when to lock a hash ? Download Code

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Re^5: threads::shared - when to lock a hash ? by ikegami (Patriarch) on Oct 17, 2011 at 06:57 UTC
So `each` isn't thread safe. That brings us to `keys`. Is `keys` uninterruptible, or just the parts that would cause corruption? Update: No, `keys` isn't thread safe either. `use strict; use warnings; use threads; use threads::shared; use feature qw( say ); use constant NUM_THREADS => 10; my %h :shared = map { $_ => 1 } 'a'..'z'; my $size = () = keys(%h); my $done :shared; my @threads; for (1..NUM_THREADS) { push @threads, async { while (!$done) { my $test_size = () = keys(%h); if ($test_size != $size) { warn("$test_size != $size\n"); return; } } }; } sleep(10); $done = 1; $_->join() for @threads;` [download] `11 != 26 42 != 26 15 != 26 38 != 26 13 != 26 41 != 26 15 != 26 41 != 26 13 != 26 45 != 26` [download]	[reply] [d/l] [select]
Re^6: threads::shared - when to lock a hash ? by choroba (Cardinal) on Oct 17, 2011 at 10:30 UTC
Nice. Adding `sort keys %h` to the warning shows really ugly things like these: `bccfkllnppqw aaaaaaaaaabbbbbbbcdddddddddeeffffffffffffggggghhhhhhhhhhhhhhiiiiiiiiii +ijjjjjjjjjjjjjjjkkkkkkkklllllllllmmmmmmmnnnnnnnnnnooooooopppppppqqrrr +rrrrrrrrrrrrrrrsstttuuuuuuuuuuuuuuuuuvvvvvwwwwwwwwwxxxxxxxxxxxxxxxxyy +yyyyyyzz acdegkqstvwyz aabcccdddeeefggghijkkklmnpqqqrrssstttuvvvwwxyyyzz` [download] And so on.	[reply] [d/l] [select]