title: Error writing to CSV - Warning: fopen() [function.fopen]: Filename cannot be empty
body: <p>On my site users fill out a form to register, this info then gets added to a database. I'm trying to get the info to be written to a CSV file also. The code I have so far gives me this error: </p>
  
  <p>Warning: fopen() [function.fopen]: Filename cannot be empty in /home/content/m/a/t/matronryan/html/sendmail3.php on line 122</p>
  
  <p>Line 122: $fp = fopen($filename, "w");</p>
  
  <p>I can't work out what the problem is. Here's the code:</p>
  
  <pre><code>$first_name = $_POST['first_name']; // required
  $last_name = $_POST['last_name']; // required
  $email_from = $_POST['email']; // required
  $stilldonate = $_POST['stilldonate']; // not required
  $phone = $_POST['phone'];
  $bid = $_POST['bid']; // required
  $item = $_POST['item'];
  $address1 = $_POST['address1']; // required
  $address2 = $_POST['address2']; 
  $city = $_POST['city'];
  $county = $_POST['county']; // required
  $postcode = $_POST['postcode']; // required
  $updated = $_POST['updated']; 
  
  include('db_functions.php');
      connect_to_db();
      $query="insert into auctionusers (firstname, lastname, address1, address2, city, county, postcode, email, phone, bid, stilldonate, item, updated) values ('$first_name', '$last_name', '$address1', '$address2', '$city', '$county', '$postcode', '$email_from', '$phone', '$bid', '$stilldonate', '$item', '$updated')";
      $result=mysql_query($query);
  
  
  $filename == 'auctionusers.csv';
  $fp = fopen($filename, "w");
  
  $res = mysql_query("SELECT * FROM auctionusers");
  
  // fetch a row and write the column names out to the file
  $row = mysql_fetch_assoc($res);
  $line = "";
  $comma = "";
  foreach($row as $name =&gt; $value) {
      $line .= $comma . '"' . str_replace('"', '""', $name) . '"';
      $comma = ",";
  }
  $line .= "\n";
  fputs($fp, $line);
  
  // remove the result pointer back to the start
  mysql_data_seek($res, 0);
  
  // and loop through the actual data
  while($row = mysql_fetch_assoc($res)) {
  
      $line = "";
      $comma = "";
      foreach($row as $value) {
          $line .= $comma . '"' . str_replace('"', '""', $value) . '"';
          $comma = ",";
      }
      $line .= "\n";
      fputs($fp, $line);
  
  }
  
  fclose($fp);
  
  mysql_close();
  
  
  header('location: index2.php?op=Thank You&amp;id=bid');
  
  }
  ?&gt;
  </code></pre>
  
  <p>Can Anyone see whats wrong?</p>