PHP Foreach Reference Gotcha

Patrick — Sat, 25 Oct 2014 12:27:03 +0000

$items = array(1, 2, 3);

foreach($items as &$item) {
    echo $item;
}

// prints: 123

echo $item;

// prints: 3

foreach($items as $item) {
    echo $item;
}

// prints: 122

What?
This happens because after the first loop $item maintains the reference to 3.

Of course PHP does not have block scoping so we then assign that reference to the current loop item in the second loop overwriting the initial value.

The fix. Always unset the item after the closing brace.

foreach($items as &$item) {
    echo $item;
} unset($item);

Or put it in a self-invoking function.

call_user_func(function() use (&$items) {
    foreach($items as &$item) {
        echo $item;
    }
});

Windows 7 64bit Sharing Brother Fax Printer with Windows XP

Patrick — Tue, 12 Jul 2011 02:57:06 +0000

The other day I had an issue with sharing a Brother Fax 2850 printer connected to Windows 7 with another Windows XP computer. Which I wanted to post for future reference.

The problem is fairly simple the driver from the Brother website here has a slightly different model name to the one detected by Windows 7.

The fix is easy just extract the driver then open the brpry4p.inf file with notepad (you may need to change the files properties so it is no longer “read-only” in order to save).

Scroll down to this line:

;; Model Name BRFAX2900.MFC = "Brother FAX-2900" BRFAX3800.MFC = "Brother FAX-3800" BRFAX2850.MFC = "Brother FAX-2850"

Should be changed to the name Windows XP has listed:

;; Model Name BRFAX2900.MFC = "Brother FAX-2900" BRFAX3800.MFC = "Brother FAX-3800" BRFAX2850.MFC = "Brother FAX-2850 USB"

After that change Windows XP should correctly detect the driver.

Patrick Galbraith » Miscellaneous

PHP Foreach Reference Gotcha

Windows 7 64bit Sharing Brother Fax Printer with Windows XP