in reply to One piece of code, two mysteries! (UPDATED.)

These 2 lines confuse me 

kill 0, $pid while sleep 1 and $timeout--;
kill 3, $pid if $timeout;

[download]
What are you trying to do here? It appears, that you repeat sleep(1) until $timeout is 0. In this case, the second line does nothing, so your thread is not terminated. Probably you wanted to have 
sleep 1 while kill(0, $pid) && $timeout--;
kill 3, $pid if $timeout;

[download]

Could it be, that running thread messes up the array?

Replies are listed 'Best First'.
Re^2: One piece of code, two mysteries!
by BrowserUk (Patriarch) on Oct 05, 2012 at 07:43 UTC

    Well spotted, you're not wrong.

    That comes about because this is an as yet incomplete modification of an old subroutine with different goals. The bugs I encountered meant that I haven't gotten around to trying finishing the modifications.

    But that has nothing to do with the error, as they are reproduced by this simplification:

    #! perl -slw
use strict;
use threads;
use threads::shared;

sub test {
    my @results :shared;
    async {
        @results = 1 .. 10;
    }->join;
    
    print "@results";
    return @results;
}

print test();

__END__
C:\test>junk50
1 2 3 4 5 6 7 8 9 10
Use of uninitialized value in print at C:\test\junk50.pl line 16.
Use of uninitialized value in print at C:\test\junk50.pl line 16.
Use of uninitialized value in print at C:\test\junk50.pl line 16.
Use of uninitialized value in print at C:\test\junk50.pl line 16.
Use of uninitialized value in print at C:\test\junk50.pl line 16.
Use of uninitialized value in print at C:\test\junk50.pl line 16.
Use of uninitialized value in print at C:\test\junk50.pl line 16.
Use of uninitialized value in print at C:\test\junk50.pl line 16.
Use of uninitialized value in print at C:\test\junk50.pl line 16.
Use of uninitialized value in print at C:\test\junk50.pl line 16.

    [download]

    I didn't switch to this as my example because I could not reproduce the circumstances of the "modification of a readonly value" with this.

    With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority".
    In the absence of evidence, opinion is indistinguishable from prejudice.

    RIP Neil Armstrong
[reply]
[d/l]

In Section Seekers of Perl Wisdom