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]

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

[lightnb]

register2.php reads:

<?PHP

$location_ID ="RVM Registration"; // Set the location variable 

// Include Database connection information 

Require('../include/SQL_connect.php');

// Include the shared registration functions

Require('../include/functions.php');

// Include the registration forms functions page

Require('../registration/registration_forms.php');


// Check to see if the form has been submited


if (isset($HTTP_POST_VARS["submit"])) //if the form has been submited, do the following
    {
    
    $title = $HTTP_POST_VARS["title"];
    $f_name = $HTTP_POST_VARS["f_name"];
    $l_name = $HTTP_POST_VARS["l_name"];
    $zip = $HTTP_POST_VARS["zip"];    
    
    $ret_error = form_validator_names($title, $l_name, $f_name, $zip);
    
    registration_form_2();
        
    }else //(if the form has not be submited)
    {
    $user_name = $HTTP_GET_VARS["user_name"];
    registration_form_2(); //display the form
    }
    
?>

[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;
} 

[lightnb]

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= 1array(2) { [0]=> array(4) { ["file"]=> string(48) "/home/rahl/public_html/RVM/include/functions.php" ["line"]=> int(217) ["function"]=> string(10) "safe_query" ["args"]=> array(1) { [0]=> &bool(true) } } [1]=> array(4) { ["file"]=> string(53) "/home/rahl/public_html/RVM/registration/register2.php" ["line"]=> int(29) ["function"]=> string(20) "form_validator_names" ["args"]=> array(4) { [0]=> &string(3) "Dr." [1]=> &string(4) "last" [2]=> &string(4) "nick" [3]=> &string(5) "23456" } } }

[NightShift58]

# array(2) {
#   [0]=> array(4) {
#     ["file"]=> string(48) "/home/rahl/public_html/RVM/include/functions.php"
#     ["line"]=> int(217)
#     ["function"]=> string(10) "safe_query"
#     ["args"]=> array(1) {
#       [0]=> &bool(true)
#     }
#   }
#   [1]=> array(4) {
#     ["file"]=> string(53) "/home/rahl/public_html/RVM/registration/register2.php"
#     ["line"]=> int(29)
#     ["function"]=> string(20) "form_validator_names"
#     ["args"]=> array(4) {
#       [0]=> &string(3) "Dr."
#       [1]=> &string(4) "last"
#       [2]=> &string(4) "nick"
#       [3]=> &string(5) "23456"
#     }
#   }
# }

The calling line is Line 29 in register2.php with the values listed.

[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]

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;
      echo "<pre>";
      print_r(debug_backtrace());
      echo "</pre>";
      exit;
    }
  }
  return $result;
} 

It should make the display a bit more readable. Make sure that you only use this when testing...

[lightnb]

Line 29 reads:

$ret_error = form_validator_names($title, $l_name, $f_name, $zip); 

and the variables:

[0]=> &string(3) "Dr."
#       [1]=> &string(4) "last"
#       [2]=> &string(4) "nick"
#       [3]=> &string(5) "23456"

are correct as well.

I don't see where it's getting "Query=1" though...

[lightnb]

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

Array
(
    [0] => Array
        (
            [file] => /home/rahl/public_html/RVM/include/functions.php
            [line] => 220
            [function] => safe_query
            [args] => Array
                (
                    [0] => 1
                )

        )

    [1] => Array
        (
            [file] => /home/rahl/public_html/RVM/registration/register2.php
            [line] => 29
            [function] => form_validator_names
            [args] => Array
                (
                    [0] => Dr.
                    [1] => last
                    [2] => nick
                    [3] => 23456
                )

        )

) 

So does:

[args] => Array
                (
                    [0] => 1
                )

mean that the safe_query function itself is setting the value to one?