Redirecting STDOUT to a FileHandle ?

[chb]

I want to redirect STDOUT to a FileHandle and I tried this:

#! /usr/bin/perl -w

use FileHandle;

$fh=FileHandle->new(">blarg");
open(STDOUT, ">&$fh") or die "Argh: $!";
print "foo bar\nbaz\n";
$fh->close();

It gives me

Argh: Invalid argument at chb.pl line 6.

After intense manual study I came across this solution:

#! /usr/bin/perl -w

use FileHandle;

$fh=FileHandle->new(">blarg");
open(STDOUT, sprintf(">&=%d", $fh->fileno()));
print "foo bar\nbaz\n";
$fh->close();

It works, but it looks really ugly. My Question is: is there a cleaner way to do this ? Have I missed some manpage ?
- chb

[jeroenes]

Read perlopentut and FileHandle.

#! /usr/bin/perl -w
 
  use FileHandle;
 
  $fh=FileHandle->new(">blarg");
  die 'Not open' unless defined $fh;
  open(STDOUT, ">&".$fh->fileno) or die "Argh: $!";
  print "foo bar\nbaz\n";
  $fh->close();

Hope this helps,

Jeroen
"We are not alone"(FZ)

[chb]

Hey, thanks, that looks better
- chb

[arhuman]

or even :


use FileHandle;

$fh=FileHandle->new(">blarg")or die "error on fh creation";
local *TOTO=$fh;
open(STDOUT, ">&TOTO") or die "Argh: $!";
print "foo bar\nbaz\n";
close(TOTO);

If ou want to go back in a known field...

"Only Bad Coders Badly Code In Perl" (OBC2IP)

[physi]

I'm not sure if you mean that:

open STDOUT ">whatever.dat";
print "Hello World";
close STDOUT;

Now have a look in whatever.dat :^)

-----------------------------------
--the good, the bad and the physi--
-----------------------------------

[chb]

No, I didn't mean that, I need a FileHandle variable which can be passed to a sub, and the sub does the redirect...
But you are right, that didn't show up in my example code...
-chb

[jbert]

And for TIMTOWTDI fans:

open( FOO, "> foo" ) or die( "End of foo is nigh : $!" );
select FOO;         # Hang on, isn't 'select' for networking?
call_legacy_code(); # Hehe, output goes to foo
exit 0;

sub legacy_code {
  # Heh...print to the screen
  print "I 0wn j000!\n";
}

Caveats:
1. printing explicitly to STDOUT will still go to STDOUT
2. This isn't what you asked
3. You can probably do this with 'FileHandle' objects but this monk is too lazy to check
4. the reputation of comments may go down as well as up, past performance is no guarantee of future success.

[Anonymous Monk]

How about something like this (it is much cleaner).

use POSIX qw(dup2);
use FileHandle ();

my $fh = FileHandle->new(">blarg");
dup2(STDOUT->fileno,$fh->fileno);

print $fh "Um... Yah\n";

I think this will be much easier to follow.

[Rhandom]

(Maybe next time I will log in first)

[Anonymous Monk]

Oh .. and if you want really short...

local $fh = \*STDOUT;

print $fh "Um... Yah\n";

I'm not sure you can get any shorter than that (with out taking out the whitespace).

[Rhandom]

(Maybe next time I will log in first )

[Rhandom]

Or yet another. This might be better than my first example because you don't have to open a file on some bad filehandle.

use POSIX qw(dup);
use FileHandle ();

my $fd = dup(STDOUT->fileno);
my $fh = FileHandle->new();
$fh->fdopen($fd,'w');

print "Um... Yah\n";

If you want it shorter...

my $fh - FileHandle->new();
$fh->fdopen(dup(fileno(STDOUT)),'w');

The first is more readable.

[isotope]

Try looking through Restoring STDOUT and STDERR after having redirected them to files, and pay special attention to the solution

--isotope
http://www.skylab.org/~isotope/

[araqnid]

use IO::Wrap;
my $stdout = wraphandle(\*STDOUT);

that sort of thing? (iirc IO::Wrap is not core, but on CPAN)