电子邮件脚本发送电子邮件但丢弃无法重新声明spamcheck（）错误

I have a script that send emails to multiple email addresses, the script is suppose to redirect to a success page upon completion, the emails are being sent fine with no problems, however I am getting up the following error instead of redirection.

Fatal error: Cannot redeclare spamcheck() (previously declared in /websites/123reg/LinuxPackage22/br/ig/ht/MYSITE.co.uk/public_html/admin/mailinglistsend.php:87) in /websites/123reg/LinuxPackage22/br/ig/ht/MYSITE.co.uk/public_html/admin/mailinglistsend.php on line 87

The code is as follows

<?php
//initialize the session
if (!isset($_SESSION)) {
  session_start();
}

require_once('../Connections/BrightLights.php'); 

if (!function_exists("GetSQLValueString")) {
function GetSQLValueString($theValue, $theType, $theDefinedValue = "", $theNotDefinedValue = "") 
{
  if (PHP_VERSION < 6) {
    $theValue = get_magic_quotes_gpc() ? stripslashes($theValue) : $theValue;
  }

  $theValue = function_exists("mysql_real_escape_string") ? mysql_real_escape_string($theValue) : mysql_escape_string($theValue);

  switch ($theType) {
    case "text":
      $theValue = ($theValue != "") ? "'" . $theValue . "'" : "NULL";
      break;    
    case "long":
    case "int":
      $theValue = ($theValue != "") ? intval($theValue) : "NULL";
      break;
    case "double":
      $theValue = ($theValue != "") ? doubleval($theValue) : "NULL";
      break;
    case "date":
      $theValue = ($theValue != "") ? "'" . $theValue . "'" : "NULL";
      break;
    case "defined":
      $theValue = ($theValue != "") ? $theDefinedValue : $theNotDefinedValue;
      break;
  }
  return $theValue;
}
}

mysql_select_db($database_BrightLights, $BrightLights);
$query_mailinglist = "SELECT * FROM mailing_list WHERE subscribed = ''";
$mailinglist = mysql_query($query_mailinglist, $BrightLights) or die(mysql_error());
$row_mailinglist = mysql_fetch_assoc($mailinglist);
$totalRows_mailinglist = mysql_num_rows($mailinglist);

error_reporting(E_ALL & ~E_NOTICE);
ini_set('display_errors', TRUE);
ini_set('display_startup_errors', TRUE);




?>
<?php 



$subject = $_POST['subject'];
$body = $_POST['body'];

do {

$name = $row_mailinglist['name'];
$email = $row_mailinglist['email'];



    $email_from = 'mailinglist@MYSITE.com';
    $email_subject = "$subject";
    $email_body = "
    $name,

    $body



    You have received this email because you have subscribed via our website, to unsubscribe go to MYSITE/mailing-list.php?unsubscribe=$email";


    $to = "$email";
    $headers = "From: $email_from";
    mail($to, $email_subject, $email_body, $headers);





    function spamcheck($field)
    {
        //filter_var() sanitizes the e-mail
        //address using FILTER_SANITIZE_EMAIL
        $field=filter_var($field, FILTER_SANITIZE_EMAIL);

        //filter_var() validates the e-mail
        //address using FILTER_VALIDATE_EMAIL
        if(filter_var($field, FILTER_VALIDATE_EMAIL))
        {
            return TRUE;
        }
        else
        {
            return FALSE;
        }
    }

    } while ($row_mailinglist = mysql_fetch_assoc($mailinglist));


mysql_free_result($mailinglist);

    header('Location: mailinglist-new.php?sent');

?>

I appreciate your help :-)

strange you are declaring function inside of do while loop

fixed code should look something like this:

<?php
//initialize the session
if (!isset($_SESSION)) {
  session_start();
}

require_once('../Connections/BrightLights.php'); 

function spamcheck($field)
    {
        //filter_var() sanitizes the e-mail
        //address using FILTER_SANITIZE_EMAIL
        $field=filter_var($field, FILTER_SANITIZE_EMAIL);

        //filter_var() validates the e-mail
        //address using FILTER_VALIDATE_EMAIL
        if(filter_var($field, FILTER_VALIDATE_EMAIL))
        {
            return TRUE;
        }
        else
        {
            return FALSE;
        }
    }


if (!function_exists("GetSQLValueString")) {
function GetSQLValueString($theValue, $theType, $theDefinedValue = "", $theNotDefinedValue = "") 
{
  if (PHP_VERSION < 6) {
    $theValue = get_magic_quotes_gpc() ? stripslashes($theValue) : $theValue;
  }

  $theValue = function_exists("mysql_real_escape_string") ? mysql_real_escape_string($theValue) : mysql_escape_string($theValue);

  switch ($theType) {
    case "text":
      $theValue = ($theValue != "") ? "'" . $theValue . "'" : "NULL";
      break;    
    case "long":
    case "int":
      $theValue = ($theValue != "") ? intval($theValue) : "NULL";
      break;
    case "double":
      $theValue = ($theValue != "") ? doubleval($theValue) : "NULL";
      break;
    case "date":
      $theValue = ($theValue != "") ? "'" . $theValue . "'" : "NULL";
      break;
    case "defined":
      $theValue = ($theValue != "") ? $theDefinedValue : $theNotDefinedValue;
      break;
  }
  return $theValue;
}
}

mysql_select_db($database_BrightLights, $BrightLights);
$query_mailinglist = "SELECT * FROM mailing_list WHERE subscribed = ''";
$mailinglist = mysql_query($query_mailinglist, $BrightLights) or die(mysql_error());
$row_mailinglist = mysql_fetch_assoc($mailinglist);
$totalRows_mailinglist = mysql_num_rows($mailinglist);

error_reporting(E_ALL & ~E_NOTICE);
ini_set('display_errors', TRUE);
ini_set('display_startup_errors', TRUE);






$subject = $_POST['subject'];
$body = $_POST['body'];

do {

$name = $row_mailinglist['name'];
$email = $row_mailinglist['email'];



    $email_from = 'mailinglist@brightlightstheatreschool.com';
    $email_subject = "$subject";
    $email_body = "
    $name,

    $body



    You have received this email because you have subscribed via our website, to unsubscribe go to brightlightstheatreschool.com/mailing-list.php?unsubscribe=$email";


    $to = "$email";
    $headers = "From: $email_from";
    mail($to, $email_subject, $email_body, $headers);

    } while ($row_mailinglist = mysql_fetch_assoc($mailinglist));


mysql_free_result($mailinglist);

    header('Location: mailinglist-new.php?sent');

?>

You declare your function in a do - while loop (what for?!) . Put it out. Everything will be ok!

Check if you have declared the spamcheck() function in any included file

-- Update

The spamcheck function is in the while loop. Which is the reason for re declaration