Description:
------------
When used repeatedly, in a loop, mail() will often hang causing the script and/or browser to timeout. Sometimes the script will continue to execute after the browser times out, causing all sorts of grief. 

I've tested this on numerous (RedHat 7.x through RH FC1) servers, and have seen the same issue since at least PHP 4.2.x. 

(Just crossed my mind to report this as a bug!) 

Reproduce code:
---------------
<?
set_time_limit(0); 
$header="From: mlist@domain.com"; 
$sql="SELECT email FROM list ORDER BY email ASC"; 
if ($res=pg_exec($dbconn, $sql)) 
 while ($row=@pg_fetch_array($res)) 
  { 
  echo $row['email']."<BR>\n"; 
  mail($row['email'], 'Mailing List News', $msg, $header); 
  } 
?>

Expected result:
----------------
user@domain.com
user@domain.com
user@domain.com 
... 10,000 times. 

Actual result:
--------------
user@domain.com
user@domain.com
user@domain.com 
... typically less than 100 times, and then browser times out.