PHP $var undefined when using multiple require()

I'm setting a $baseurl in a settings.php file.

In my index.php, I've got 3 require() in a row for the settings.php/header.php/masthead.php.

When I come to echo out the $baseurl it's undefined开发者_JAVA百科. If I define the $baseurl within the header.php then it works within the header.php file.

How can I get the $baseurl to be defined within the settings.php file and usable within each require() ?

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Order of inclusion

The file that sets $baseurl must be require_once() first for the subsequent files to have access to the variable.

Function Scope

If you are defining $baseurl in a function or the files are require_once() from within a function then $baseurl will be trapped in that functions scope. This would the case if settings.php looked something like:

<?php
function setup_config() {
    $baseurl = 'http://www.example.org';
}

Or requiring from within a function

<?php
function include_a_file($file) {
    require_once 'my/base/path/' . $file;
}

This is documented in the Variable Scope portion of the PHP Manual.

One way to work around this is to add $baseurl as an element in $GLOBALS array instead of as a standalone variable:

$GLOBALS['config']['baseurl'] = 'my/base/url/';

Note I have added the ['config'] element to namespace your config away from anything else you may be tempted to place in $GLOBALS.

variable unset()

Another possibility is that you might be calling unset($baseurl) somewhere else in the code, which would be marking the variable as undefined.

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If you define it in settings.php, it should be available in the global scope of all the included scripts. When you enter a function, the scope changes so the variable won't be available unless you 'import' it by declaring global $baseurl; at the start of the function (not advised, though).

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If settings.php is included first, and $baseurl is defined as a global variable in settings.php, it will be available in all subsequently included files. If the variable is defined inside a function in settings.php, it will need to be defined as a global there:

$GLOBALS['baseurl'] = 'theurl';

If it is accessed within a function in any of the subsequently included files, it will need to be accessed via $GLOBALS[] there too:

echo $GLOBALS['baseurl'];

If you are expecting to access a global variable from multiple files, it is highly recommended to always use the $GLOBALS[] array since it remains clear in any scope that the variable is being set and accessed globally.

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If you require() the files in a function, the variables are defined in the scope of the function: They are not global.

Use $GLOBALS['baseurl'] = '...'; in settings.php