global variables in php mess my html up!

Question

I have a problem. When I use global variables in my php code, my server doesn't show any html code at all. If I comment out the global variable, my html page works just fine! Am I doing something wrong here?

php file:

class DBConnect{

    // If I comment this out, the HTML shows
    global $con;

    function connectDB() {
        $user = "bstokni_basurin";
        $pass = "basurin";
        $database = "basurin";
        $host = "localhost";

        $this->$con = mysql_connect($host, $user, $pass) or die(mysql_error());
        echo "Connected to MySQL </br>";
        echo $con;
    }

    function closeDB() {
        mysql_close($con);
        echo $con;
        echo "MySQL closed";
    }   
}

html file:

<!-- Left colon -->
            <div id="leftCol">
                <p>Her kemur ein menu at standa</p>
                <?
                    $menuObj = new DBConnect();
                    $menuObj->connectDB();
                ?>
            </div>

What am I doing wrong here?

You're getting a PHP error but the errors are suppressed. Put this at the top of the page and tell us what you get error_reporting(E_ALL); ini_set('display_errors', '1'); — Swift
– Swift, Commented Jun 25, 2011 at 2:36
@Mike Swift - It could also be that styles are just hiding the error or warning. @hogni89, have you tried selecting the text in the vicinity of the problematic div, or tried installing custom error handlers? — user50049
– user50049, Commented Jun 25, 2011 at 2:38

Brian · Accepted Answer · 2011-06-25 02:38:16Z

3

Since the variable is in a class scope, try changing global to public instead. You don't seem to need global in the example you have provided.

answered Jun 25, 2011 at 2:38

Brian

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3 Comments

Jimmy Sawczuk Over a year ago

And it's probably not expected, meaning it's (as Mike Swift points out) throwing a suppressed error. Here's a proof: codepad.org/b5JsmgPx

hogni89 Over a year ago

Thanks for your answer. I'm new to class in PHP. I had two problems. First of all: $this->$con = ... should be: $this->con = ... And changing from global to public also worked :) I can go to sleep now ;)

Brian Over a year ago

Add function __construct() { global $test; } and change global $test; in your current project to public $text;. It will set the variable as global when the class is instantiated.

Jimmy Sawczuk · Accepted Answer · 2011-06-25 02:43:51Z

3

Shouldn't:

$this->$con

be:

$this->con

?

If you're just trying to access a member variable named con. Everywhere else you refer to is by just $con, why the $this in the one place? I'm not sure what $this->$con is supposed to do, but I'm guessing it is affected by whether or not $con has been declared global.

edited Jun 25, 2011 at 2:43

Jimmy Sawczuk

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answered Jun 25, 2011 at 2:42

Ben

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4 Comments

Jimmy Sawczuk Over a year ago

$this->$con will try to access the public variable named whatever the value of $con is. See this example. In his case, $this->$con is some MySQL resource that will probably be wrongly interpreted as a string.

meteorainer Over a year ago

Ya the extra $ will blow it up every time. But you need to checking your errors too, so do as suggested by mike swift as well.

Ben Over a year ago

I had a feeling. But the contents of $con would be null in both cases, wouldn't they? So $this->$con = ... should be assigning to the same (wrong) place whether there is a global $con declaration or not. So how does one case work and the other not?

Jimmy Sawczuk Over a year ago

global isn't correct to use as a class variable (I misspoke earlier, it doesn't matter that it's a public or private variable in this case, just a class variable), that's what the error was. In my case, I'm only assigning one class variable; it only prints the one it knows about.

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