Can't use function return value in write context

[lightnb]

I have a function that's supposed to query mysql with a zip code, and generate an html <select> box with possible cities. Instead, it crashes the site and gives this error:

Fatal error: Can't use function return value in write context in /home/rahl/public_html/RVM/include/functions.php on line 298

The content of the function is:

function zip_code_city_handler($zip)
    {

    global $zip;
    
    $query = "SELECT * FROM zip WHERE zip = '$zip'";
    
    $result = safe_query($query);
        
    if (mysql_num_rows($result) = 1)
        {
        $city_select = "<select>";
        while($row = mysql_fetch_array($result))
            {
            $city_select .= "<option>".$row['city']."</option>";
            }
        $city_select .= "</select>";
        }
        else
        {
        $row = mysql_fetch_array( $result );
        $city_select = $row['city'];
        }
        
        return $city_select;
    } 

I've never gotten this error before and I'm not really sure what it means...

Any help is appreciated, as always.

Thanks,

Nick

[NightShift58]

It means that your function is returning an unspeakable value - make that unwritable value. True and false are examples of that.

You have a coding error in the function:

if (mysql_num_rows($result) = 1) 

This resolves to a value assignment and not a condition test. Use "==" instead of "=".

[lightnb]

oops... That fixed the error. Thank you

Now I'm getting:

# errorno=1064
# error=You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '1' at line 1
# query=query

I think this is causing the problem:

    if(empty($error))
        {
        $query = mysql_query("UPDATE Users SET title='$title',last_name='$l_name',first_name='$f_name',zip='$zip' WHERE handle='$user_name'") 
        or die(mysql_error());  
        
        safe_query($query); 

[NightShift58]

Change the function safe_query as follows:

function safe_query ($query = "")
    {
    if(empty($query))
        {
        return FALSE;
        }
    $result = mysql_query($query)
        or die("I've Failed You: <li>errorno=".mysql_errno()."<li>error=".mysql_error()."<li>query=".$query);
    return $result;
    } 

(Missing "$" in final "query".)

[lightnb]

wow. how do you always find the needle in the haystack? (or the missing $ in 3000 lines of code)

I now get:

query=1 

So I'm guessing the query got screwed up somewhere...

[NightShift58]

wow. how do you always find the needle in the haystack? (or the missing $ in 3000 lines of code)

Probably because I make more mistakes than you do...

[NightShift58]

On second thought, I would change it to this:

function safe_query ($query = "") {
  $result = FALSE;
  if (!empty($query)) {
    $result = @mysql_query($query);
    if (!$result) {
      echo "I've Failed You:<br>";
      echo "<li>Script Name: " . $_SERVER['PHP_SELF'];
      echo "<li>Include File: " . __FILE__;
      echo "<li>errorno=" . mysql_errno();
      echo "<li>error="   . mysql_error();
      echo "<li>query= "  . $query;
      exit;
    }
  }
  return $result;
} 

[lightnb]

Error now reads:

I've Failed You:
# Script Name: /RVM/registration/register2.php
# Include File: /home/rahl/public_html/RVM/include/functions.php
# errorno=1064
# error=You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '1' at line 1
# query= 1

[NightShift58]

Try this:

function safe_query ($query = "") {
  $result = FALSE;
  if (!empty($query)) {
    $result = @mysql_query($query);
    if (!$result) {
      echo "I've Failed You:<br>";
      echo "<li>Script Name: " . $_SERVER['PHP_SELF'];
      echo "<li>Include File: " . __FILE__;
      echo "<li>errorno=" . mysql_errno();
      echo "<li>error="   . mysql_error();
      echo "<li>query= "  . $query;
      var_dump(debug_backtrace());
      exit;
    }
  }
  return $result;
} 

[bokeh]

	if(empty($error))
		{
		$query = mysql_query("UPDATE Users SET title='$title',last_name='$l_name',first_name='$f_name',zip='$zip' WHERE handle='$user_name'") 
		or die(mysql_error());  
		
		safe_query($query);

I don't understand what is going on here. Anyway I was right about a boolean. It is an UPDATE query and mysql_query is returning true. Then for some reason you are running that boolean as if it were another query. Also what is the point having that function if you never use the return value for anything.

[NightShift58]

I don't understand what is going on here. Anyway I was right about a boolean. It is an UPDATE ...

Where did you find this snippet?

EDIT: Found it... Didn't see it before... Should be:

if(empty($error)) {
        $query = "UPDATE Users SET title='$title',last_name='$l_name',first_name='$f_name',zip='$zip' WHERE handle='$user_name'";
        $result = safe_query($query); 

EDIT: Based on Bokeh's observation...

[bokeh]

safe_query($query); 

Yeah, but you also need to pick up the return value and do something with it.

[bokeh]

This is probably happening because your form uses the POST method.

[lightnb]

I've switched to session variables to handle all of the passing of information from one page to another, and I have *most* everything working.

I'm having trouble with my email confirmation page now, and I can't figure out why. It changes the database corectly, but it isn't printing the error or confirmation method.

I've been working on it for a couple hours now and I can get the message to print under the table, but not inside it!


This is the confirmation page:

<?PHP
session_start( );
$location_ID ="RVM Email Confirmation"; // Set the location variable 

// Include the registration forms functions page
Require('../registration/registration_forms.php');

// Include Database connection information 
Require('../include/SQL_connect.php');

// Include the shared registration functions
Require('../include/functions.php');


// get the confirmation code
$code = $HTTP_GET_VARS["confirmation_code"];

check_confirmation_code($code);

//$_SESSION["return_message"] = check_confirmation_code($code);



?>

and this is the function that goes with it:

function check_confirmation_code($code)
    {
    $query = "SELECT * FROM Users WHERE confirmation_code = '$code'";
    $result = safe_query($query);
    if (mysql_num_rows($result) > 1)
        {
        $return_message = "AAAAAAAAHHHHHHHHHHHHHH!!!!!!!!!!!!!!!!!!!!!!!<br/> Something has gone teribly wrong. Please email technical support,
        or <a href='../registration/dc_request.php' class='inline_link'>request a new confirmation code here</a>.";
        
        // draw the page
        registration_email_confirmation();    
        
        }
        elseif (mysql_num_rows($result) < 1)
        {
        $return_message = "I'm sorry, but the confirmation code you have entered isn't valid.<br/>Please be sure you are using the
        code provided in your confirmation email, and that you are doing so within 24 hours of receiving it.
        If you need to, you may <a href='../registration/dc_request.php' class='inline_link'>request a new confirmation code here</a>.";
    
        // draw the page
        registration_email_confirmation();    
        
        }
        elseif (mysql_num_rows($result) == 1)
        {
        
        $row = mysql_fetch_array( $result );
                
        session_register("l_name");
        $_SESSION["l_name"] = $row['last_name'];
        
        session_register("title");
        $_SESSION["title"] = $row['title'];
        
        session_register("user_name");
        $_SESSION["user_name"] = $row['handle'];
        
                session_register("email");
        $_SESSION["email"] = $row['email'];
        
        session_register("confirmation_code");
        $_SESSION["confirmation_code"] = $row['confirmation_code'];
        
        $return_message = "Thank you, ".$_SESSION["title"]."&nbsp;".$_SESSION["l_name"].".<br/><br/><br/>
        You are now registered under the username: ".$_SESSION["user_name"]." Using the email address: ".$_SESSION["email"]."
        <br/><br/> From here, you can <a href='../interface/user_home.php' class='inline_link'>go to your homepage</a>.... more options when I acctually code somewhere to go.";
        
        $query = "UPDATE Users SET confirmation_code='0',confirmed='1' WHERE confirmation_code='".$_SESSION["confirmation_code"]."'";
        $result = safe_query($query);
        
        // draw the page
        registration_email_confirmation();
        
        }
    
    } 

and this is the function that prints the HTML, and *should* be printing out the $return_message variable inside of it:

function registration_email_confirmation()
    {
    
    // Include the header information

    global $return_message;

    Require('../include/header.php');
    
    echo "
    
<table align='center' background='http://www.rahlentertainment.com/RVM/Images/registration/register_generic.jpg' border='0' width='778px' height='379px'>

<! ROW ONE >

    <tr height='75px'>
        <td>
        
        </td>
    </tr>
    
<! ROW TWO >

    <tr height='35px'>
        <td>
        <Table border='0'>
            <tr>
                <td width='240px'>
                
                </td>
                <td width='450px' align='left'>
                </td>
                <td>
                </td>
            </tr>
        </table>
        </td>
    </tr>

<!ROW THREE>
    <tr height='120px' valign='top'>
        <td>
            <table width='522px' align='right'>
                <tr>
                    <td>
                    <div class='form_instructions'>
                    ".$return_message."
                    </div>
                    </td>
                </tr>
            </table>
        </td>
    </tr>

<! ROW FOUR >

    <tr height='89'>
        <td>
        
        </td>
    </tr>
    
<! ROW FIVE >

    <tr>
        <td>
        <table border='0'>
            <tr>
                <td width='131'>
                
                </td>
                <td>
                <a href='#' class='small_text_links'>Terms of Use</a>
                </td>
                <td width='346px'>
                </td>
                <td>
                <a href='#' class='small_text_links'>Privacy Policy</a>
                </td>
            </tr>
        </table>
        </td>
    </tr>
</table>
    ";
    
    }