PHP函数无法正常工作（回显字符串，简单）

Question

I created a function to allow me to debug PHP scripts so long as a variable ($debug) is set to 1:

function debug($msg) {
    if ($debug == 1) {
        echo $msg;
    } else {
        return false;
    }
}

That way, at the top of my script (before the functions.php file is called), I write:

$debug = 1;

to enable debugging, then:

debug("Function executed: " . $data);

at certain points so that I know string values/whatever at that point, with the desired response being the message displayed upon the screen.

However, regardless of what the value of the $debug string is, I never see any echo'd statements.

How can this be achieved?

Answer 1

It's difficult to say because you provided too few data.

The reason can be that your $debug variable is not known inside a function. Because using globals is not adviced, consider using constants define("DEBUG",1);.

EDIT

I presented within another question how I use a class for doing the same thing as class names are also globally accessed.