Hello, i am new to the monastery and hope this is the right place for my question. I want to redirect the standard output from a perl function. This function can contain print and system commands. I cannot modify this function! I tried the following: 

# this is my sample function i cannot modify
sub doIt() {
    print "blabla\n";
    print STDOUT "blabla2\n";
    #sample_app is a small script that writes some output to STDOUT an
+d STDERR
    system("sample_app");
}

sub execute() {
    pipe(RDR, WTR);
    my $pid = fork();
    if ($pid == 0) {
        
        close STDOUT;
        open (STDOUT, '>&WTR');
        select STDOUT;
        $| = 1;

        doIt();

        print "child finished\n";
        exit;
    } else {

        my $buf = "";
        while ($buf !~ /child finished/) {
            $buf .= <RDR>;
        }
        sleep 2;
        print "parent got:\n$buf\n";
    }
}

[download]
if i call execute() i get the output i exspected. $buf contains all the output (including the messages from the system command). Thats fine :) Now i tried this with threads. 
use threads;
my $t = threads->new(\&execute);
$t->join();

[download]
Unfortunately this doesnt do what i expected. The output of the system command is written to the shell (and not to my pipe). At the end of the execution $buf only contains "blabla" and "blabla2". Is there a way to get this working in a threaded environment?

In reply to Redirecting stdout with threads by michi

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