note 70998 added to language.variables.scope

From: Date: Tue, 07 Nov 2006 18:35:08 +0000
Subject: note 70998 added to language.variables.scope
Groups: php.notes 
Request: Send a blank email to php-notes+get-119485@lists.php.net to get a copy of this message
davo971 (http://us2.php.net/manual/en/language.variables.scope.php#69765), it seems you're encountering the same mental block that jason (http://us2.php.net/manual/en/language.variables.scope.php#65337) was having. I know how that goes, because I used to have this problem as well. Don't think of permission to access a variable as being transferred from function to function. There is exactly 1 global scope in any script, and that's the scope outside of all functions and classes. If you specify a variable as global, it does not mean you are accessing a variable in the calling function's namespace, it means you are accessing the variable in the global namespace. In your example, you seemed to think that declaring $new_var global in function2() would give it access to variables declared in function1()'s namespace. In fact, acess to variables does not propagate up the function stack--declaring you wish to work on a global variable ALWAYS gives you access to the SINGLE variable declared in the global namespace with that name. It's more easily understood when you work with the $GLOBALS array... there's only 1 such array, and consequently there's exactly 1 of each global variable. So if we modify your example to work correctly, here's what it'll look like: <?php $var = 'foo'; $new_var = 'asdf'; function function1() { global $new_var; //Now working with global $new_var, declared above $new_var = 'bar'; //Changing $new_var from 'asdf' to 'bar' function2(); } function function2() { global $var, $new_var; //Accessing global variables $var and $new_var, declared outside any functions echo($var . $new_var); } function1(); ?> Outputs foobar ---- Server IP: 64.71.164.2 Probable Submitter: 128.174.73.20 ---- Manual Page -- http://www.php.net/manual/en/language.variables.scope.php Edit -- https://master.php.net/note/edit/70998 Del: integrated -- https://master.php.net/note/delete/70998/integrated Del: useless -- https://master.php.net/note/delete/70998/useless Del: bad code -- https://master.php.net/note/delete/70998/bad+code Del: spam -- https://master.php.net/note/delete/70998/spam Del: non-english -- https://master.php.net/note/delete/70998/non-english Del: in docs -- https://master.php.net/note/delete/70998/in+docs Del: other reasons-- https://master.php.net/note/delete/70998 Reject -- https://master.php.net/note/reject/70998 Search -- https://master.php.net/manage/user-notes.php

« previous php.notes (#119485) next »