wp_installing

WordPress Version: 5.5

/**
 * Check or set whether WordPress is in "installation" mode.
 *
 * If the `WP_INSTALLING` constant is defined during the bootstrap, `wp_installing()` will default to `true`.
 *
 * @since 4.4.0
 *
 * @param bool $is_installing Optional. True to set WP into Installing mode, false to turn Installing mode off.
 *                            Omit this parameter if you only want to fetch the current status.
 * @return bool True if WP is installing, otherwise false. When a `$is_installing` is passed, the function will
 *              report whether WP was in installing mode prior to the change to `$is_installing`.
 */
function wp_installing($is_installing = null)
{
    static $installing = null;
    // Support for the `WP_INSTALLING` constant, defined before WP is loaded.
    if (is_null($installing)) {
        $installing = defined('WP_INSTALLING') && WP_INSTALLING;
    }
    if (!is_null($is_installing)) {
        $old_installing = $installing;
        $installing = $is_installing;
        return (bool) $old_installing;
    }
    return (bool) $installing;
}