Edit report at http://bugs.php.net/bug.php?id=52937&edit=1
ID: 52937
Updated by: cataphr...@php.net
Reported by: mryaggi at hotmail dot com
Summary: call_user_func warning is inappropriate
Status: Open
Type: Bug
Package: Scripting Engine problem
Operating System: Seven
PHP Version: 5.3.3
Block user comment: N
New Comment:
You *should* know whether the function takes references; it's part of
its signature.
If it does take references you cannot use call_user_func, and have to
use call_user_func_array instead.
Previous Comments:
------------------------------------------------------------------------
[2010-09-29 19:31:10] mryaggi at hotmail dot com
Thank you for your quick reply.
You say : "Use call_user_func_array()."
But you can run the test script with call_user_func_array() instad, and
still you will get those warnings.
My point is : when you call call_user_func you have no idea whether the
function called expects references or not (values).
The only solution I see is to always give references to
call_user_func*()
For ex:
-----------------
function MY_call_user_func_array($Func,$Args)
{
foreach(array_keys($Args) as $i) { $Args[$i] =& $Args[$i]; }//make it
a ref
call_user_func_array($Func,$Args);
}
function test(&$z){ echo "ok : " . $z . "\n";}
$a = 1;
MY_call_user_func_array('test',array($a));
-----------------
And here we are! IT WORKS!
but it I feel like I just learnt how to poo in PHP...
------------------------------------------------------------------------
[2010-09-28 03:13:28] cataphr...@php.net
Yes, this may be confusing. The problem is that the level of indirection
added means when the function test() is actually called by the
implementation of call_user_func() via zend_call_function, information
about the arguments is lost. Use call_user_func_array().
Tests 1 and 3 are basically the same. The manual for call_user_func has
a note:
«Note that the parameters for call_user_func() are not passed by
reference.»
Since call_user_func doesn't receive its parameters by reference, by the
time they reach it, it has no way of knowing if the parameters were sent
by reference or not.
Test 2 is a different matter. But you are actually passing a reference
to test() because zend_call_function() is nice and when you pass a
non-reference to a function that expects a reference and the
non-reference has refcount 1, it converts it into a reference. See
http://lxr.php.net/opengrok/xref/PHP_TRUNK/Zend/zend_execute_API.c#860
Again, this makes sense if you're writing an extension and using
zend_call_function() and passing it a variable you've created. I don't
see how this can be fixed, except by adding something like
fci->no_separation that doesn't create a reference even if the refcount
is 1. Not sure if it's worth the trouble.
------------------------------------------------------------------------
[2010-09-27 19:31:16] mryaggi at hotmail dot com
Description:
------------
call_user_func now issue a warning in PHP5.3 when giving a value instead
of a
reference.
However, this warning shows up in inappropriate cases.
Test script:
---------------
<?php
//Function to be called via call_user_func
function test(&$z)
{
echo "ok : " . $z . "\n";
}
// - 1 : With a local variable
//This should work, but...
$a = 1;
call_user_func('test',$a);//Warning: Parameter 1 to test() expected to
be a reference, value given
// - 2 : Giving a constant
//This should issue a warning but ...
call_user_func('test',2);//works fine. Output "ok : 2"
// - 3 : Base on a parameter
//This should work, but ...
function test3($p=3)
{
call_user_func('test',$p);//Warning: Parameter 1 to test() expected to
be a reference, value given
}
test3();
?>
Expected result:
----------------
ok : 1
<b>Warning</b>: Parameter 1 to test() expected to be a reference, value
given in
...
ok : 3
Actual result:
--------------
<b>Warning</b>: Parameter 1 to test() expected to be a reference, value
given in
...
ok : 2
<br />
<b>Warning</b>: Parameter 1 to test() expected to be a reference, value
given in
...
------------------------------------------------------------------------
--
Edit this bug report at http://bugs.php.net/bug.php?id=52937&edit=1
