#31798 [Bgs]: set_error_handler() object argument passed by value,not reference

ID: 31798 User updated by: vl409 at yandex dot ru Reported By: vl409 at yandex dot ru Status: Bogus Bug Type: Documentation problem Operating System: linux-2.4.25,freebsd 4.10 PHP Version: 4.3.10 New Comment: thank you for your work on php bugs - i already understood what happens; i just think that if people understand documentation wrong in some place, it`s worth to mention details in it. in this case, it seems to me usefull to mention that in php4 set_error_handler() can`t be called in constructor, because of.. (link on object creation docs) again, thank you for your work and good luck =) Previous Comments: ------------------------------------------------------------------------ [2005-03-15 14:39:37] vrana@php.net It's expected and documented behavior, take a look at the chapter References Explained. What's happening? &$this is a reference to the current object, but "$x=new" assigns a copy of this object to $x. Thus error handler is now method in object which is not referenced by any variable. You can achieve the desired behavior by using &$this together with $x=&new (or use PHP 5, but take a look at http://php.net/migration5.oop first). ------------------------------------------------------------------------ [2005-02-02 16:31:12] vl409 at yandex dot ru I thought about this problem and think that documentation should better explain how objects in PHP are created. I removed set_error_handler() call from constructor to method of error handling class and called this method right after object creation. This works. So, what we should understand, is when object is actually created ? It seems to me that when in constructor i assign values to $this->smth, $this is not the same to what returned when i call $obj=new Something, thats why set_error_handler(&$obj,"method") doesnt work in this case. am i right? =) ------------------------------------------------------------------------ [2005-02-01 22:13:42] sniper@php.net reclassified ------------------------------------------------------------------------ [2005-02-01 21:55:05] vl409 at yandex dot ru Description: ------------ Possibly,it`s a duplicate bug of Bug #25128 set_error_handler not sending reference http://bugs.php.net/bug.php?id=25128&edit=2 I tried to write my own class for handling errors in php and found that if i call set_error_handler with argument, being object(&$this), it is passed by value, not by reference. This is strange, because function set_error_handler is declared same as call_user_func, but behaves differently. as defined in manual: mixed call_user_func ( callback function...) mixed set_error_handler ( callback error_handler...) I tested example on FreeBSD 4.1/PHP 4.3.10 and Linux 2.4.25/PHP 4.3.5 Code,demonstrating this, provided below. P.S. If it`s a duplication, then you can mean this report as BUG IN DOCUMENTATION! I found that i wanted to do almost the same as man in Bug #25128, but due to lack of documentation, spent a lot of time for nothing... Reproduce code: --------------- <?php class error_handler { var $error_count; function error_handler(){ $this->error_count=0; set_error_handler(array(&$this,'handler')); echo "<b>New error handler registered!</b><br>"; } function handler() { echo "Cought an error! increasing counter!<br>"; $this->error_count++;} function show(){ echo "This object handled ".$this->error_count." errors<br>"; } } $x=new error_handler; $x->show(); trigger_error("Ooops!",E_USER_ERROR); $x->show(); trigger_error("Ooops!",E_USER_ERROR); $x->show(); echo "<b>called by call_user_func:</b><br>"; call_user_func(array(&$x, "handler")); $x->show(); echo "<b>called manually</b><br>"; $x->handler(); $x->show(); ?> Expected result: ---------------- New error handler registered! This object handled 0 errors Cought an error! increasing counter! This object handled 1 errors Cought an error! increasing counter! This object handled 2 errors called by call_user_func: Cought an error! increasing counter! This object handled 3 errors called manually Cought an error! increasing counter! This object handled 4 errors Actual result: -------------- New error handler registered! This object handled 0 errors Cought an error! increasing counter! This object handled 0 errors Cought an error! increasing counter! This object handled 0 errors called by call_user_func: Cought an error! increasing counter! This object handled 1 errors called manually Cought an error! increasing counter! This object handled 2 errors ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=31798&edit=1