Empty() function might not be working with Constants in PHP
<p>I've been looking at it for a while and cannot figure out what the problem might be:</p>

<p>My Code:</p>

<pre><code>&lt;?php

    session_start();

    require "includes/config.php";
    require "includes/database.php";
    require "twitteroauth/twitteroauth.php";

    if(empty(CONSUMER_KEY) &amp;&amp; empty(CONSUMER_SECRET))
    {
        exit("Please define Consumer Key and Consumer Secret Keys");
    }

    $connection = new TwitterOAuth(CONSUMER_KEY,CONSUMER_SECRET);
    $request_token = $connection-&gt;getRequestToken(OAUTH_CALLBACK);

    // Temporary credentials to make requests to Twitter
    $_SESSION["oauth_token"] = $request_token["oauth_token"];
    $_SESSION["oauth_token_secret"] = $request_token["oauth_token_secret"];

    switch ($connection-&gt;http_code)
    {
        case 200:
            $url = $connection-&gt;getAuthorizeURL($request_token);
            header("Location:".$url);
            break;
        default:
            die("Connection to Twitter failed. Please try again."); 
    }

?&gt;
</code></pre>

<p>And the error is:</p>

<pre><code> ## 
Parse error: syntax error, unexpected ')', expecting T_PAAMAYIM_NEKUDOTAYIM in /home/.../connect.php on line 9
 ##
</code></pre>

<p>The line 9 part starts from </p>

<pre><code>if(empty(CONSUMER_KEY) &amp;&amp; empty(CONSUMER_SECRET))
{
    exit("Please define Consumer Key and Consumer Secret Keys");
}
</code></pre>

<p>CONSUMER_KEY and CONSUMER_SECRET, they are constants and defined in "includes/config.php" like below:</p>

<pre><code>$config = parse_ini_file("config.ini");
define("CONSUMER_KEY",$config["TwitterAPI"]["Consumer_Key"]);
define("CONSUMER_SECRET",$config["TwitterAPI"]["Consumer_Secret"]);
</code></pre>
