declaring class instance inside/outside a function

[BigBadKev]

Hi all,

I am a serious glutton for this error : "Call to a member function on a non-object"…

I have created a debug class to output a debug.txt file for debugging purposes and was getting this error and thanks to you guys I finally found out that I needed to declare the object as global in every single function as I was trying to make a superglobal or superclass type construct so that I could always refer to my debug object from anywhere.

Well this saga gets a little stranger, I am now using the php function "set_error_handler" and have come across the same type of problem but it is when i declare the class itself within the function versus declaring the class outside of the function,

include("c:\\Debug.php");

set_error_handler("cust_err_hand");

//do something flakey to cause a error like 
$string = "newbie";
join('', $string); 

//This fails....
function cust_err_hand($type, $msg, $file, $line)  {
  $x = new Debug;
  global $x;
  $x->s("function cust_err_hand");
  $x->s("Type : $type");
  .......etc...etc....
}

//This works....
$x = new Debug;
function cust_err_hand($type, $msg, $file, $line)  {
  global $x;
  $x->s("function cust_err_hand");
  $x->s("Type : $type");
  .......etc...etc....
}

The only difference is the declaring of the class outside/inside a function.
The debug class is in another php file from this one that is calling it.

Is this a case of object persistence? Like does the object declared outside the function persist and when created inside the function have a destructer or destroy type behavior?

Thanks again guys

BBK
😃

[lanjoky]

dont know if this will make a difference but ... where you have

function cust_err_hand($type, $msg, $file, $line)  { 
  $x = new Debug; 
  global $x; 
  $x->s("function cust_err_hand"); 
  $x->s("Type = $type"); 
  .......etc...etc.... 
} 

change to

function cust_err_hand($type, $msg, $file, $line)  { 
  global $x; //switched this line with line under it!!
  $x = new Debug;
  $x->s("function cust_err_hand"); 
  $x->s("Type = $type"); 
  .......etc...etc.... 
} 

HTH

[BigBadKev]

Hi lanjoky and others,

wow that worked but I dont know why?

So is it: declare scope then declare what type of object it is always in php or is this a special case? I would have thought they were interchangeable in regards to order?

Hey a big thank you

BBK
😃

[Jack_Slocum]

Instead of declaring the empty variable gobal beforehand, you could just use the globals array. i.e.

$x = new Debug();
$GLOBALS['x'] = $x;

or

$GLOBALS['x'] = new Debug;
$GLOBALS['x']->s("blah blah");

[lanjoky]

yup you delcare the scope (if not defualt) and then declare type ... then initiate ... thats the order for PHP

[BigBadKev]

Hi guys,

One final question is this the same?

//example 1
$x = new Debug; 
function cust_err_hand($type, $msg, $file, $line)  { 
  global $x; 
  $x->s("function cust_err_hand"); 
  $x->s("Type : $type"); 
  .......etc...etc.... 
}
//example 2
function cust_err_hand($type, $msg, $file, $line)  { 
  global $x;
  $x = new Debug; 
  $x->s("function cust_err_hand"); 
  $x->s("Type : $type"); 
  .......etc...etc.... 
}

BBK
😃

[ahundiak]

Not really.

In the first case you always create one and only one instance of the debug class. In the second case you create a new instance each time the error handler is called.

A slight variation would be to create the debug object the first time the error handler is called.

$x = null;

function cust_err_hand($type, $msg, $file, $line) {
global $x;
if ($x === null) $x = new Debug;
...