FAQ 5.7 How can I make a filehandle local to a subroutine? How do I pass filehandles betw...

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5.7: How can I make a filehandle local to a subroutine?  How do I pass
filehandles between subroutines?  How do I make an array of filehandles?

    As of perl5.6, open() autovivifies file and directory handles as
    references if you pass it an uninitialized scalar variable. You can then
    pass these references just like any other scalar, and use them in the
    place of named handles.

            open my    $fh, $file_name;

            open local $fh, $file_name;

            print $fh "Hello World!\n";

            process_file( $fh );

    Before perl5.6, you had to deal with various typeglob idioms which you
    may see in older code.

            open FILE, "> $filename";
            process_typeglob(   *FILE );
            process_reference( \*FILE );

            sub process_typeglob  { local *FH = shift; print FH  "Typeglob!" }
            sub process_reference { local $fh = shift; print $fh "Reference!" }

    If you want to create many anonymous handles, you should check out the
    Symbol or IO::Handle modules.


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