Is it better to pass variables to a function?

stephen_c_ · October 16th, 2005, 10:08 AM

I've read on lots of sites that register_globals in the php ini should be turned off and that instead of using

global variableName;

in functions to access variables you should pass variables to functions as arguments.

Is this faster? Better? Safer? If so, why?

Some of my functions need access to loads of variables, I find it easier to just use 'gloabls variableName;'. Should I try and convert my code to used passed arguments? These could be passed by reference, so that the variables outside functions could be updated. Wouldn't this be pretty much like just using a variable ina function with the global prefix before it?

anshul · October 19th, 2005, 01:38 PM

global variables are a bad idea.
Pass variables to a function; which makes code modular.
Still better if you wite class definition, instantiate an object and they call function on it (object).

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robprell · November 3rd, 2005, 10:15 PM

if register_globals has exploits and you can do it easily without doing things that way. Why increase the risk of your application by using register_globals? There are plenty of exploits to worry about why create one more? Its cleaner, better, safer code to pass variables to a function. Although the wrox basic php book uses register_globals in it's examples please grow past the shortcomings of this book.....

stephen_c_ · November 4th, 2005, 05:07 AM

Some of my functions have lots of variables currently accessed through the keyword global.

e.g.

Code:

    function loginForm($errorMessage = "no_error")
    {
        global $self;
        global $loginMessage;
        global $loginPassword;
        global $loginUsername;
        global $loginKeepLogged;
        global $loginSubmit;
        global $loginReset;
        global $loginLanguage;
        global $loginDefaultLang;
        global $loginTheme;
        global $loginDefaultTheme;

        ...rest of function
    }

I think maybe I can put all these variables by reference into an array (using a new function) and just pass the array by reference to the function. Would this work? A variable passed by reference twice, would the original still get upadated?