thanks for the reply. I was looking to the source code of Tie::STDOUT. He basically solves it with something like:

    open(my $stdout, ">&", STDOUT); 
...
# in the overloaded method PRINT
    $stdout->print( @_ ); # this refers to the original STDOUT.
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I guess this opens a different underlying file handle, while my $oldhandle = STDOUT is an assignment/alias to the same file handle used by STDOUT.

s.fox