global vs passing argument

[spires]

Hi

 

Simple question.

Is there a reason why you should use global over passing an argument into a function,

or visa versa?

 

example:

 

Global

$var = 1;
function test(){
    global $var;
    $var++;
    return $var;
}

 

 

Passing Argument

$var = 1;
function test($var){
    $var++;
    return $var;
}

 

 

Is it just a matter of preference?

 

 

Thanks

[premiso]

Some people use the globals for "ease of use" and not having to always add that parameter to the function.

 

The preferred way, especially if you plan on distributing the script, is passing the variable as a parameter to the function. This way anyone should techincally be able to see how to use it and what it expects to be passed in, vs having to dig through all your code to find out which global variable it takes in etc.

[KevinM1]

Rule of thumb - global should never be used.

[spires]

ok great.

So they are in effect exactly the same. But passing arguments is the more preferred method.

 

I never normally use global, but a few books and training courses seem talk about using it.

I've never seen the point as I just pass the variable. So just thought I'd check I wasn't missing something.

 

Thanks for that

[ignace]

Not to mention that you can't use the function before you made sure the global variable actually contains the required value.