Re: One piece of code, two mysteries!

[andal]

These 2 lines confuse me

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

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;

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

[BrowserUk]

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.

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.