Problem declaring variables

[Davidc316]

Hi,

I understand that newer versions of PHP have recently tightened up the way variables are declared and handled.

So, if I simply say:

print $firstname;

Then I'll get an error message which says (something like):

Notice: Undefined variable: firstname in C:\wamp\www\test\index.php on line 2

---

Also, to make the nightmare worse, if I say

$firstname=$_GET['firstname'];

...then I get a wonderful new error which is as follows:

Notice: Undefined index: firstname in C:\wamp\www\test\index.php on line 4

---

My question, of course, is "How do I sort this out?". But before telling me to initialise the variables or read the manual (I've already looked) please let me add one more detail...

I understand that I can initialise the variables by saying things like...

$firstname=""; 

or even...

$_GET['firstname]="";

This simple fix does indeed make the error messages disappear. BUT WAIT! Let's not crack open the campaign yet!

If I declare $_GET['firstname]' to NULL (nothing or whatever) then I have totally destroyed the original purpose of the GET variable - which is to read variables from the URL. How can I ever read variables from the URL if at the top of all the scripts I'm declaring those variables as being equal to nothing.

I'm on my knees begging for help.

[dagon]

one way:

if(!empty($_GET['firstname']) ){
$firstname=$_GET['firstname']; 
}else{
$firstname='';
}

[NogDog]

Note this is probably nothing new (at least not in the last 10 years or so), but rather a change in your error-reporting settings. If you have "notice" level warnings enabled and display_errors turned on, then you'll see those notices when applicable whether running PHP4 - PHP6 (and I suspect older versions, but I've not used them).

The crux of the matter is that if you try to reference a variable or array element that is not defined, it could be an indication of a logic bug or a simple typo, and the notice is intended to help the programmer by saying, "Uh, excuse me: is that really what you meant?"

As Dagon has suggested, assuming it's not a logic error or a typo, the "fix" is to test for any variable's existence if there is a question as to whether it may or may not be set before trying to use it. Do note that there is a subtle difference between empty() and isset();

<pre><?php
var_dump(isset($foo)); // false
var_dump(empty($foo)); // true

$foo = null;
var_dump(isset($foo)); // false  -- null is considered "not set"
var_dump(empty($foo)); // true

$foo = 0;
var_dump(isset($foo)); // true -- any non-null value is considered "set"
var_dump(empty($foo)); // true -- 0, boolean false, and "" are considered "empty"

$foo = 1;
var_dump(isset($foo)); // true
var_dump(empty($foo)); // false
?></pre>

[Davidc316]

Thanks folks. I really appreciate your help.

It's a shame that I've got to go through all of my sites and add IF equations all over the place - but I guess that's the way it goes.

Cheers.

[NogDog]

Or you can cheat and turn off display_errors or change the [man]error_reporting/man level. 😉

[dagon]

i vote for cheating, i guess its one of my very bad habits but i have codded hundreds of sites all without taking note of that particular notice. Hope the boss is not reading this :-)