RFC: allow_call_pass_by_reference

Is it me, or the wiki post talks about param and return by ref?

Return by ref is not related to call-time pass by ref, is it?

See zend_compile.c.

Anyway, my opinion is clear on that one: shoot that dead cow. It's
been deprecated for years, and you should declare your function
prototypes with the param by ref anyway if you need it.

Did you bother to read the proposal or did you just hit send? What exactly
do you think the RFC is about?

• Steph

For anyone else who doesn't read to the end...

Anyway, my opinion is clear on that one: shoot that dead cow. It's
been deprecated for years, and you should declare your function
prototypes with the param by ref anyway if you need it.

All I'm asking is that we throw a warning by default in 5_3, because in PHP
6 there isn't even an option to switch that warning off. To be frank this
shouldn't ever have needed to go to an RFC; the lack of warning is an
obvious bug in PHP which should simply be fixed.

• Steph

Hi Derick,

I don't think we should get rid of it, or add a notice/message/whatever.
Because this:

http://pastebin.com/d6e055957

could not be done without call time pass by ref right now. So unless
that's fixed, we shouldn't deprecate it.

Hm. Actually those 'expected values' are wrong because 12 is itself an array
and so isn't seen as an array element. But I take your point.

On the other hand, call_time_pass_reference already is deprecated and has
been for the last 8 years, so maybe fixing PHP to allow it where it makes
sense might be a good way to go?

Johannes mentioned call_user_func() on irc too:

<?php

function increment(&$var) {
$var++;
}

$a = 0;
call_user_func('increment', $a);
echo $a;

Warning: Parameter 1 to increment() expected to be a reference, value given
in...
0

$b = 0;
call_user_func('increment', &$b);
echo $b;

Deprecated: Call-time pass-by-reference has been deprecated; If you would
like to pass it by reference, modify the declaration of call_user_func().
If you would like to enable call-time pass-by-reference, you can set
allow_call_time_pass_reference to true in your INI file in...
1

The manual advises that you use call_user_func_array() instead - which
doesn't throw a warning - and virtually all the user notes recommend
variable functions as both faster and safer than call_user_func(). So why
isn't that deprecated if call_time_pass_reference is?

• Steph

Derick Rethans wrote:

I looked into it again (and found things I didn't know before). This one's
bugging me enough that I braved the Wiki:

http://wiki.php.net/rfc/calltimebyref

I don't think we should get rid of it, or add a notice/message/whatever.
Because this:

http://pastebin.com/d6e055957
This pastebin expired, but is the same as:

http://pastebin.com/f1d8c08e8

and: http://bugs.php.net/bug.php?id=45126

could not be done without call time pass by ref right now. So unless
that's fixed, we shouldn't deprecate it.

regards,
Derick

• Mark

Hi,

There is a use case for the function allowing explicitly call-time pass by
reference, because the function works both ways in subtly different ways.

I have some libraries where I had to have variations of the functions like
"AbcByRefr()" and "Abc()", because of this inflexibility.

In a perfect world, here's how I'd do it, of course the actual syntax can be
something else (this also improves the understanding of the code as it makes
the intent explicit, versus implicit at call time, as it is now):

function foo(& $a) {} // allows only explicit pass by reference

foo($a); // illegal, error
foo(& $a); // legal, pass by reference

function bar($a) {} // forbids pass by reference

foo($a); // legal, pass as 'copy'
foo(& $a); // illegal, error

function baz(&? $a) {} // acknowledges that it functions properly and
accepts both ways

foo($a); // legal, pass as 'copy'
foo(& $a); // legal, pass as reference

Regards,
Stan Vassilev

Sometimes call time pass by reference is useful, for example when you
want to make it possible to omit an param (normally passed by
reference) by setting null. With no call time pass by reference,
programmers are required to write:

$null = null;
foo($null);

what stops you from declaring:

function someFunc(&$param = null)
{
}

it works just fine

Deleting it isn't a good idea, it should become a normal (not
deprecated) language feature.

--
Alexey Zakhlestin
http://blog.milkfarmsoft.com/

2008/5/22, Alexey Zakhlestin indeyets@gmail.com:

Sometimes call time pass by reference is useful, for example when you
want to make it possible to omit an param (normally passed by
reference) by setting null. With no call time pass by reference,
programmers are required to write:

$null = null;
foo($null);

what stops you from declaring:

function someFunc(&$param = null)
{
}

it works just fine
And what if this param isn't the last param of this function, and next
params are required?