in reply to fork() interferring with backtick

why would the fork() interfere with the results from the backticks in line 8?
It could, if you'd have your own SIG{CHLD} handler, but you don't.

In second your example you are performing 1 fork call per @dir entry, and in first for each @dir entry * each @makelist entry

So those two examples are completelly different

I would suggest to minimize it to proof-of-concept code, so everyone could reproduce problem:
Remove `find ...` call, use `cat somefile` insted, don't use directory traversal. Minimize the code so it don't do anything unrelated to fork.

Replies are listed 'Best First'.
Re^2: fork() interferring with backtick
by mkaiser67 (Initiate) on Oct 16, 2013 at 18:37 UTC
    Actually I do have a SIG{CHLD} handler. It occurs before the code block: 
    my $queue = [];
sub REAP {
    my $kidpid;
    while(($kidpid = waitpid(-1,WNOHANG)) > 0) {
        #p rint "reaped $kidpid\n";
        push @$queue, [ $kidpid, $? ];
    }
}
$SIG{'CHLD'} = \&REAP;

    [download]
    i didn't include it earlier thinking it didn't matter
[reply]
[d/l]
      REAP called for external programs called with backtricks, however it seems it does not affect anything in your case. 
      my $queue = [];
sub REAP {
    my $kidpid;
    print STDERR "HANDLER\n";
    while(($kidpid = waitpid(-1,WNOHANG)) > 0) {
        print STDERR "reaped $kidpid\n";
        push @$queue, [ $kidpid, $? ];
    }
    print STDERR "/HANDLER\n";
}
$SIG{'CHLD'} = \&REAP;

`echo 1`;

my $pid = fork();
print STDERR "FORK CHILD $pid\n" if $pid;
exit unless ($pid);

print STDERR "before sleep\n";
sleep 2;
print STDERR "after sleep\n";
print STDERR "DONE\n";
__END__


HANDLER
/HANDLER
FORK CHILD 29104
before sleep
HANDLER
reaped 29104
/HANDLER
after sleep
DONE

      [download]
[reply]
[d/l]
        I think my problem has to do with http://www.perlmonks.org/?node_id=1026468 I'm running 5.14 - my system hasn't been upgraded yet
[reply]

In Section Seekers of Perl Wisdom