Re: [PHP-DEV] Passing-by-reference From: Andi Gutmans (andi <email protected>)
Date: 11/23/00

At 03:11 PM 11/23/00 -0500, Ignacio Vazquez-Abrams wrote:
>On Thu, 23 Nov 2000, Andi Gutmans wrote:
>
> > a) Do you prefer to document the three ways which work foo($a), foo(bar())
> > where bar() is defined as function which returns a reference, and foo(new
> > testclass) and all the rest will be documented as undefined.
> > b) Do you want to define the "undefined" behavior in some way, i.e.,
> always
> > create a copy of the returned data and pass it.
> >
> > Thanks,
> > Andi
> > ---
> > Andi Gutmans <andi <email protected>>
> > http://www.zend.com/
> >
>
>c) Throw an error. More than likely this will indicate a coding problem, and
>just passing a copy will cause a developer to scratch her head and say
>"WTF?" for several months while trying to figure out the problem(s). Leaving
>behavior as undefined will just cause memory corruption problems for sloppy
>developers, which is what we want to get away from in the first place.

Throwing an error is a problem because we can't really detect it. With my
patch the undefined behavior will not cause memory corruption anymore but
will either throw an error or continue working (i.e. undefined).
In the manual it would say something like:
Receiving arguments by reference:
----------------------------------------
Three ways of passing an argument to a function which wants to receive its
argument by reference:
a) foo($a) // Passing a variable
b) foo(new foo()) // Passing a newly created object
c) foo(MyFactory()) // Where MyFactory() is explicitly defined to return
the return value by reference, which is done by defining it as "function
&MyFactor(){...}"

ALL OTHER ARGUMENT PASSING RESULTS IN UNDEFINED BEHAVIOR!

How's that? :)
Andi

Andi 

---
Andi Gutmans <andi <email protected>>
http://www.zend.com/

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