php 5.3 - Error message: Fatal error: Can't use function return > value in write context in -

i trying run code book. there appears problem code.

here error message:

fatal error: can't use function return value in write context in /applications/mamp/htdocs/eclipse-workspace/simpleblog/test.php on line 24

here code referenced in message (starting on line 24)

if (!empty(trim($_post['username']))          && !empty(trim($_post['email']))) {          // store escaped $_post values in variables              $uname = htmlentities($_post['username']);              $email = htmlentities($_post['email']);               $_session['username'] = $uname;               echo "thanks registering! <br />",                  "username: $uname <br />",                  "email: $email <br />";          }  

i appreciate help. please let me know if need provide more information

---

thanks lot guys. fast. solution works great.

the problem empty() function needs applied direct variables.

for future reference: code 'php absolute beginners' jason lengstorf (2009), pages 90-91, chapter 3, $_session

corrected code:

    //new - created variable can passed empty() function     $trimusername = trim($_post['username']);      //modified - applying empty function correctly new variable      if (!empty($trimusername)      && !empty($trimusername)) {       // store escaped $_post values in variables      $uname = htmlentities($_post['username']);      $email = htmlentities($_post['email']);       $_session['username'] = $uname;       echo "thanks registering! <br />",          "username: $uname <br />",          "email: $email <br />";  }  

in short: empty() function works directly on variables

<?php empty($foo); // ok empty(trim($foo)); // not ok 

i'd say, course of getting further book, use temporary variable

so change:

if (!empty(trim($_post['username']))  

to

$username = trim($_post['username']); if(!empty($username)) {       //....