Problems with Filehandles and TeeOutput

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

I am trying to use TeeOutput to capture STDOUT to temporary file. I can get it to work with old stye, uppercase global filehandles, but cannot get it to work using proper filehandle variables.

#!/usr/bin/perl -w
use Local::TeeOutput;
use IO::File;
use strict;

local *LOG;
open (LOG, ">>test.out");
openTee(*STDOUT, *STDOUT, *LOG);
print "One\n";
closeTee(*STDOUT);


my $fh = IO::File->new(">>test.out");
openTee(*STDOUT, *STDOUT, $fh);
print "Two\n";
closeTee(*STDOUT);
[download]

Note that only "one" gets written to test.out. The documentation for TeeOutput states "The filehandle must be passed as an unquoted typeglob." I am not sure how to achieve that from a regular filehandle. (Note I actually want to store result in string variable but this is the first step) Any help appreciated.

Comment on Problems with Filehandles and TeeOutput Download Code

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Re: Problems with Filehandles and TeeOutput by ikegami (Patriarch) on Aug 26, 2008 at 02:49 UTC
Looking at the source, the inputs to `openTee` must be a glob (`ref(\$file) eq 'GLOB'`), a string expression starting with "`>`" or "`>>`", or a file name (opened for append). Based on some quick testing (without the module), all of these should work `local LOG; open(LOG, '>>test.out'); openTee(STDOUT, STDOUT, LOG); my $fh = IO::File->new(">>test.out"); openTee(STDOUT, STDOUT, $fh); open(my $fh, '>>', 'test.out'); openTee(STDOUT, STDOUT, $fh); openTee(STDOUT, STDOUT, '>>test.out'); openTee(STDOUT, STDOUT, 'test.out');` [download] By the way, why do you want to use IO::File instead of open anyway?	[reply] [d/l] [select]
Re^2: Problems with Filehandles and TeeOutput by hkpatv (Initiate) on Aug 26, 2008 at 05:24 UTC
OK, here is the results of my testing: `#Works local LOG; open(LOG, '>>test.out'); openTee(STDOUT, STDOUT, LOG); #Does not work my $fh = IO::File->new(">>test.out"); openTee(STDOUT, STDOUT, $fh); #Does not work open(my $fh, '>>', 'test.out'); openTee(STDOUT, STDOUT, $fh); #Does not work open(my $fh, '>>', 'test.out'); openTee(STDOUT, STDOUT, $fh); #Works openTee(STDOUT, STDOUT, '>>test.out'); #Works openTee(STDOUT, *STDOUT, 'test.out');` [download] Note the resason I am using IO::File is because actually I want to use IO::File->new_tmpfile, but as that doesn't work I am trying IO::File->new to make testing easier. Note the only reason I was trying to get new_tmpfile working was cause I couldn't get it into a string using scalar I/O `open($fh, "+<", \$string);` [download]	[reply] [d/l] [select]
Re^3: Problems with Filehandles and TeeOutput by ikegami (Patriarch) on Aug 26, 2008 at 05:56 UTC
Sorry, but the module you are using wasn't written to work on lexical handles, introduced over 8 years ago with 5.6. Update: IO::Tee appears to work with lexical file handles as well.	[reply]
Re^4: Problems with Filehandles and TeeOutput by hkpatv (Initiate) on Aug 26, 2008 at 09:24 UTC
Re^5: Problems with Filehandles and TeeOutput by ikegami (Patriarch) on Aug 26, 2008 at 18:08 UTC
Re^3: Problems with Filehandles and TeeOutput by massa (Hermit) on Aug 26, 2008 at 09:41 UTC
I couldn't help but notice that you used `#Does not work open(my $fh, '>>', 'test.out'); openTee(STDOUT, STDOUT, $fh);` [download] instead of `#Should be working open(my $fh, '>>', 'test.out'); openTee(STDOUT, *STDOUT, $fh); #asterisks ONLY before STDOUT, NOT $fh` [download] would you mind testing once more? []s, HTH, Massa (κς,πμ,πλ)	[reply] [d/l] [select]
Re^4: Problems with Filehandles and TeeOutput by ikegami (Patriarch) on Aug 26, 2008 at 17:27 UTC
Re^4: Problems with Filehandles and TeeOutput by hkpatv (Initiate) on Aug 27, 2008 at 01:33 UTC
Re: Problems with Filehandles and TeeOutput by massa (Hermit) on Aug 26, 2008 at 02:25 UTC
Your `$fh` variable is not a regular filehandle, but an IO::File instance. Try `open my $fh, '>>', 'test.out';` [download] in your second example and tell us what happens. (I don't have TeeOutput installed to test...) []s, HTH, Massa (κς,πμ,πλ)	[reply] [d/l] [select]
Re: Problems with Filehandles and TeeOutput by apl (Monsignor) on Aug 26, 2008 at 10:52 UTC
You might also want to consider testing the success of your open before going on. That is, replace `open (LOG, ">>test.out");` [download] with `open (LOG, ">>test.out") or die "Failed to open test.out: $!";` [download]	[reply] [d/l] [select]