[Q] package "IO::Handle"

[bill]

If I try STDOUT->foo("bar") in the debugger I get:

DB<1> STDOUT->foo("bar")
Can't locate object method "foo" via package "IO::Handle" (perhaps you forgot to load "IO::Handle"?) at (eval 25)[/usr/share/perl/5.6.1/perl5db.pl:1521] line 2.

....but

DB<2> p ref STDOUT

DB<3> p ref *STDOUT

DB<4>

How come Perl treats STDOUT as an IO::Handle object in <1>, but
ref does not report any class in <2> or <3>?

TIA,

-bill

 

[Steve Grazzini]

DB<1> STDOUT->foo("bar")
Can't locate object method "foo" via package "IO::Handle" [...]
DB<2> p ref STDOUT

DB<3> p ref *STDOUT

DB<4>

How come Perl treats STDOUT as an IO::Handle object in <1>, but
ref does not report any class in <2> or <3>?

Long story short, the object is in the IO slot of *STDOUT.

print ref *STDOUT{IO};

You were looking at the string "STDOUT" and the glob *STDOUT,
neither of which are references.

Truth is, this is also a bareword string:

STDOUT->foo();

But during the method call Perl does some DWIMery to figure out
whether the string is supposed to be the name of a package or of
a filehandle.

Note the quotes:

% perl -e '"STDOUT"->foo'
Can't locate object method "foo" via package "IO::Handle"...

And the package:

% perl -e 'local STDOUT; STDOUT->foo'
Can't locate object method "foo" via package "STDOUT"...