Colin Guthrie wrote:
> Stut wrote:
>> Colin Guthrie wrote:
>>> Stut wrote:
>>>> Stut wrote:
>>>>> In that case you need a new foo. That's the only way you're going to
>>>>> reset the internal static if the API doesn't give you a way to do it.
>>>>>
>>>>> $f=new foo();
>>>>> $f->bar();
>>>>> $f->bar();
>>>>> $g=new foo();
>>>>> $g->bar();
>>>> Actually, scratch that, won't work. Not even unsetting $f before
>>>> creating the new object works. This kinda sucks since it means PHP does
>>>> not support static function-scoped vars.
>>> Yeah I tried that same thing too and then wondered if I had
>>> misinterpreted how function-scoped statics worked.
>>>
>>> I've often used a method like:
>>>
>>> function Init()
>>> {
>>> static $bln_inited = false;
>>> if (!$bln_inited)
>>> {
>>> // Do stuff
>>> $bln_inited = true;
>>> }
>>> }
>>>
>>>
>>> I had always assumed that the static definition here was
>>> function-scoped... I guess I should have tested more but still it caught
>>> me off guard this morning when I played with it.
>>>
>>> Correct me if I'm wrong but does C++ not do it as both of us initially
>>> thought? e.g. static is function scoped rather than globally scoped when
>>> used within a class method?
>> Yes it does, which is why I assumed PHP would do it like that too. I
>> knew I should have tried it before sending the reply.
>>
>> I've tried various ways of accessing that variable via a derived class
>> but it doesn't seem to be possible. Again I'm just assuming, but my
>> theory is that the line...
>>
>> static $foobar = false;
>>
>> ...actually is static to the function and therefore cannot be accessed
>> from outside it in any way, shape or form.
>>
>> So using function statics as you have above will work fine. And they
>> also work fine when used in a method of a class. This behaviour is
>> correct because if a function-scoped static is to work correctly there
>> should be absolutely no way to get at it from outside the function.
>
> I completely agree that there should be no way to access it outside the
> function/method it is defined within. The problem is that in PHP the
> static keyword seems to be globally unique but function/class scoped.
> e.g. that if it is used in a class method, regardless of how many
> instances of that method you create with "new" there is only ever one
> "instance" of the variable.
>
> So the case where it wont work fine is when you have the above function
> as a method of a class which can have multiple instances, all of which
> need to be Init()'ed independently.
>
> In such cases, I guess you'd have to use a private member variable
> instead which just isn't quite a neat and tidy.
>
> If you only ever have one instance of the class then all is well but
> still could have unexpected side effects if you later extend the system
> to have more than one instance. I guess if you use a singltron method
> with a private constructor then it's safe enough but then you can just
> do your initialisation in the singletron method in that case so there's
> little point!
>
> Hey ho.
>
> /me scuttles of to grep code for "static" :s

Nope, not globally unique: http://dev.stut.net/php/funcstatic.php

So what you have will be fine.

-Stut

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