STDERR and STDOUT can be localized, like any other global file handle, . That done you can call your function and output will go to the new handle. In perl 5.8,

my ($errors, $output);
sub foo {
    print STDERR "Something to worry about\n";
}

{
    open local(*STDERR), '>', \$errors;
    foo();
}

warn "STDERR ought to be restored now";
$errors =~ s/Something/Nothing/;
print $errors;
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Thanks, I didn't know about that. What I'm trying to do is to catch the output from Test::Harness, something like the following after your example:

use strict;
use Test::Harness;
my $out;
{
    open local(*STDOUT),'>',\$out;
    runtests();
}
print $out;
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Somehow all results are still printed out to screen, not to the $out variable. I tried STDERR too, the same result. Thanks.

Your use of the idiom is correct. The trouble is that Test::Harness does its own IO remapping.

You could try running tests from the command line and redirecting output from there.

After Compline,
Zaxo

Sorry, forgot to login for the above post.

use strict;
use warnings;

$SIG{'__WARN__'} = \&whandler;
my ($Errors);

warn "Going to call foo()\n";
foo();

print "\nErrors:\n$Errors";


sub foo
{
    # this could be a loop that takes some time to finish.

    warn "Something to worry about\n";
    warn "Something else to worry about\n";
    bar();
}

sub bar { warn "Darn it.\n" }

sub whandler
{
    my $msg = shift;
    my $caller = (caller(1))[3] || '';
    if($caller eq 'main::foo') {
        $Errors .= $msg;
    }
    else { warn $msg }
}
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Hi, if I have a function that writes something to STDOUT or STDERR, for example:

If you want to capture both STDOUT and STDERR, why not have a look at IPC::Open3? You need Open3 (AFAIK) if you want to capture STDERR. As a plus, I'm fairly certain that IPC::Open3 doesn't require a version of Perl >= 5.8. In fact, I just grepped through my perldelta pages and my perl561delta specifies that it was first included at that release.