Using a constant in a php switch in php 5.5.9

问题

After installing PHP 5.5.9 on Ubuntu 14 I found this strange behavior with a switch statement and the PHP_OS constant.

I presume that in PHP 5.5.9 the switch statement is also checking for the same type (===)?

Or is it a PHP bug?

echo PHP_OS; // Linux
$os = PHP_OS;

switch (PHP_OS) {
    case "WINNT":
        echo 'Windows';
        break;
    case "Linux":
        echo 'Linux';
        break;
    default:
        echo 'Default';
        break;
}
// Default

switch ((string) PHP_OS) {
    case "WINNT":
        echo 'Windows';
        break;
    case "Linux":
        echo 'Linux';
        break;
    default:
        echo 'Default';
        break;
}
// Default

switch ($os) {
    case "WINNT":
        echo 'Windows';
        break;
    case "Linux":
        echo 'Linux';
        break;
    default:
        echo 'Default';
        break;
}
// Linux

回答1:

PHP switches use loose comparison like == so it should match.

could you try :

switch (constant("PHP_OS"))

来源：https://stackoverflow.com/questions/25645533/using-a-constant-in-a-php-switch-in-php-5-5-9