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Date: Fri, 20 Jul 2012 12:43:54 -0400
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Subject: Re: [PHP-DEV] Recommended way to create a zval that serves as a
 callback in an extension
From: adamjonr@gmail.com (Adam Jon Richardson)

On Thu, Jul 19, 2012 at 2:49 PM, Sara Golemon <pollita@php.net> wrote:
> Same as you would in PHP code.  Make an IS_STRING pointing at a global
> function, or IS_ARRAY pointing at a class method, or an IS_OBJECT supporting
> __invoke().  If you're asking how you can call a C function directly via
> this callback: You can't.  You can can, however, make an internal method to
> use as a callback, just bear in mind it'll be callable by userspace as well.

Thank you very much for your explanation, Sara. I got my code working,
but I must confess I wasn't confident it was the preferred approach
and I wanted to make sure I was learning the recommended approach.
I've taken to heart the many examples in your book where you bring up
the most obvious/likely method to do something in the extension world
only to find out it's not the preferred/correct approach.

Thank you very much for the clarification.

Adam

P.S. - Your book has aged exceedingly well, and it's a great reference
for people like me trying to find their way around the internals :)
Nice writing style!