Re: [PHP-DEV] _sleep(),__wakeup(), phpticks From: Andrei Zmievski (andrei <email protected>)
Date: 12/11/00

On Mon, 11 Dec 2000, André Langhorst wrote:
> Do we have no information about __sleep()/__wakeup() and the way how php
> ticks work? I just realized that there is no information about them in
> the documentation deleting some old mails...

Someone was going to write docs about ticks, let me check. Ok, Daniel
Beckham contacted me and I sent him some docs on what they are about,
but apparently, no docs materialized out of that?

Well, anyway, here's an accumulation of several messages.

----------------------

I've just added support for userland PHP tick callback functions. This
can be used to simulate background processing. Usage example:

<?

function foo($a)
{
        print "$a\n";
}

function zoo()
{
        static $i = 0;

        print "I am: $i\n";
        $i++;
}

register_tick_function("foo", "I'm here!");
register_tick_function("zoo");

declare (ticks = 3)
{
    1;1;
    1;1;
    1;1;
}

?>

This would output:

I'm here!
I am: 0
I'm here!
I am: 1

It's also possible to use array($obj, 'method') syntax for callbacks,
and there is unregister_tick_function() as well.

----------------------

Ok, basically, Zend engine has a feature where after execution of a
certain number of statements (ticks) it can call another function. This
ia all C API for now. What I've done is made that C function go through
a list of PHP registered functions and call them one-by-one after the
specified number of 'ticks' has been executed.

So, in a nutshell, you register a callback function that gets called
after N statements have been executed. N is controlled by 'declare'
directive, e.g.:

declare (ticks=4) {
...
}

Anything inside the directive block will enable ticks functionality and
will call the registered functions every 4 statements.

It's possible to register the same function more than once. The
functions are executed in the order they were registered, not
simultaneously. It's possible to register array($obj, 'method') as a
callback as well.

----------------------

On Wed, 06 Sep 2000, Daniel Beckham wrote:
> Ok, I believe I get the gist of what it is supposed to do. How is the
> number of ticks determined? I'm afraid that I've never used declare() in my
> PHP code before and I don't see it mentioned in the docs anywhere, although
> I see it in "Zend/zend-scanner.l". Or was that to illustrate a point? =)

It's a new construct. It's only used for ticks for now, but may be used
for something else in the future.

declare(keyword = arg) { .. }

Basically used to apply some options to the enclosed code. For ticks it
would be:

declare (ticks = N) { .. }

Where N is the number of ticks after which the functions will be called.

> Also, let me make sure I'm clear on a few things:
>
> The statements (ticks) are referring to C statements in Zend, or user
> written PHP statements? I'm assuming that it's C statements in Zend, but I
> want to be absolutely clear.

No, it's user written PHP statements.

> It looks like the tick function you register won't necessarily be executed
> in a consistent manner, or only however long it takes to execute a certain
> number of tick statements?

Yes, if you have enclosed 3 statements that are in the for loop that is
repeated 10 times then you have 30 statements total I believe (unless
Zend splits them up a little differently). Anyway, it's not meant as a
precise tool, more like "do this every once in a while".

> And lastly, the arguments [, mixed arg [, ... ]] for
> register_tick_function() are arguments for the function name supplied?

Yes, exactly.

----------------------

-Andrei

"I think it would be a good idea." -- Mahatma Gandhi,
when asked what he thought of Western civilization... 

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