ZEND PHP 5 Certification STUDY GUIDE

44 ” Functions
// Remove the defined argument from the beginning
array_shift($args);
foreach ($args as $arg) {
$count += strlen($arg);
}
}
}
$count = 0;
countAll($count, "foo", "bar", "baz"); // $count now equals 9
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Note—and this is very important—that only variables can be passed as by-reference
arguments; you cannot pass an expression as a by-reference parameter.
Unlike PHP 4, PHP 5 allows default values to be specified for parameters even
when they are declared as by-reference:
function cmdExists($cmd, &$output = null) {
$output = ‘whereis $cmd‘;
if (strpos($output, DIRECTORY_SEPARATOR) !== false) {
return true;
} else {
return false;
}
}
In the example above, the $output parameter is completely optional—if a variable is
not passed in, a new one will be created within the context of cmdExists() and, of
course, destroyed when the function returns.
Licensed to 482634 - Amber Barrow (itsadmin@deakin.edu.au)