For each identifier in a package, there is a symbol table entry containing slots for each of the possible types with that identifier as its "name". E.g. if we have a variable $x, a subroutine &x, an array @x, these are all held in a typeglob *x. If one sets *y = *x, then *y contains the same slots that *x does, so, for example, $y is the same as $x. One can access slots of a typglob: for example, *x{SCALAR} is a reference to $x. Using typeglobs or references to typeglobs one can pass filehandles to a subroutine. For example, 
 sub blah {
          my $filehandle = shift;
           print $filehandle "Blah!\n";
           }
        blah(*STDOUT);    #these both
        blah(\*STDOUT);   #produce Blah! (and a newline)

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chas
(Updated to fix typo.)

In reply to Re: Perplexed by typeglobs. by chas
in thread Perplexed by typeglobs. by Anonymous Monk

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