in reply to Why does "flush filehandle" work?

You hit upon an (older) corner of perl's OOP syntax, the "indirect object" notation. Since flush is a method what your first code really translates to would be $gp->flush (which would be the proper replacement if you want to be explicit). In recent perls you can als disable it with no feature q{indirect}. See https://www.effectiveperlprogramming.com/2020/06/turn-off-indirect-object-notation/ for a bit more detailed explanation.

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Re^2: Why does "flush filehandle" work?
by ikegami (Patriarch) on Jan 29, 2025 at 14:28 UTC

    It's even disabled by default in the feature bundle for 5.36+ 

    $ perl -e'flush STDOUT;'

$ perl -e'no feature qw( indirect ); flush STDOUT;'
Bareword found where operator expected (Do you need to predeclare "flu
+sh"?) at -e line 1, near "flush STDOUT"
syntax error at -e line 1, near "flush STDOUT"
Execution of -e aborted due to compilation errors.

$ perl -e'use v5.36; flush STDOUT;'
Bareword found where operator expected (Do you need to predeclare "flu
+sh"?) at -e line 1, near "flush STDOUT"
syntax error at -e line 1, near "flush STDOUT"
Execution of -e aborted due to compilation errors.

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