Teeing STDOUT and STDERR to files using filehandle references

isotope has asked for the wisdom of the Perl Monks concerning the following question:

I have an application where I would like to capture STDOUT and STDERR to files, given references to their filehandles... Ideally I would tee them so shell redirection would still work. Here are some relevant code snippets:

The code that actually opens the file and returns the filehandle reference:

sub open_logfile
{
    my $filename = shift;

    # Our filehandle reference object
    local *FH;

    # Attempt to open the file
    if(open(FH, "> " . $filename))
    {
    # Opened the file
    print $FH_STATUS "Opened logfile: " . $filename . "\n";
    select(FH);
    $| = 1;         # Unbuffer
    select(STDOUT); # Restore default print to STDOUT
    return *FH;     # Return the new fh reference
    }
    else
    {
    # Couldn't open the file...
    print $FH_ERROR "Problem opening logfile: \n";
    print $FH_ERROR $filename . ":\n";
    print $FH_ERROR $! . "\n";
    print $FH_ERROR "Redirecting logging to Error log\n\n";
    sleep 5;
    return $FH_ERROR;
    }
}
[download]

Code that I would likely use to tee the output:

use IO::Tee;
$FH_STATUS = new IO::Tee(\*STDOUT, 
              new_logfile(name_logfile('logs/QTStatus')));
[download]

And then redirect all STDOUT to the new $FH_STATUS. If I can get that working, I'll do the same with STDERR.

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

Comment on Teeing STDOUT and STDERR to files using filehandle references Select or Download Code

Replies are listed 'Best First'.
Re: Teeing STDOUT and STDERR to files using filehandle references by isotope (Deacon) on Dec 16, 2000 at 04:03 UTC
This works: `STDOUT = $FH_STATUS;` [download] Anyone have a good reason not* to do it this way? --isotope http://www.skylab.org/~isotope/	[reply] [d/l]
Re: Teeing STDOUT and STDERR to files using filehandle references by isotope (Deacon) on Dec 16, 2000 at 01:03 UTC
Okay, lemme clarify a bit... the part I can't figure out how to do is redirecting STDOUT to $FH_STATUS. --isotope http://www.skylab.org/~isotope/	[reply]
Re: Re: Teeing STDOUT and STDERR to files using filehandle references by repson (Chaplain) on Dec 16, 2000 at 07:30 UTC
How about dupping the filehandle: `sub open_logfile { my $filename = shift; open STDOUTBACK, '>&STDOUT' or die "Can't dup STDOUT\n"; open STDOUT, '> ' . $filename or die "can't write to $filename: $!\n +"; }` [download] In this case any attempt to `print "foo\n"` or `print STDOUT "foo\n"` will go to the logfile. Or just use select: `sub open_logfile { my $filename = shift; open FH, '> ' . $filename or die "Can't write to $filename: $!\n"; select FH; }` [download] In the second case `print "foo\n"` will print where you want but `print STDOUT "foo\n"` will still go to the real STDOUT.	[reply] [d/l] [select]
Re: Re: Re: Teeing STDOUT and STDERR to files using filehandle references by isotope (Deacon) on Dec 18, 2000 at 22:11 UTC
This is correct, but it's not the solution to my problem... I'm redirecting to existing filehandles, not opening new files. --isotope http://www.skylab.org/~isotope/	[reply]
Re: Re: Teeing STDOUT and STDERR to files using filehandle references by cwest (Friar) on Dec 16, 2000 at 01:22 UTC
check perltie for tying file handles... there's also IO::Handle for that task. -- Casey I am a superhero.	[reply] [d/l]