Description:
------------
The introductory page about exceptions in PHP5 is lacking some basic information with some good, ready-to-use examples:

1. Throwing an exception and catching an exception are two separate things. The exception can be caught everywhere in the code.

2. The exception is passed through the call stack, until the exception is caught or a fatal error occurs.

This information is part of an user contributed note from 06-May-2005 07:15, but is vital enough to appear in the documentation itself.

Reproduce code:
---------------
http://www.php.net/manual/en/language.exceptions.php
http://www.php.net/manual/en/language.exceptions.php#52612

Expected result:
----------------
<?php
function a($x) {
  echo 'Calling function a($x), $x='.$x."\n";
  if ($x < 0) {
    $error = 'Error: $x < 0';
    throw new Exception($error);
  }
}

function b($y) {
  echo 'Calling function b($x), $y='.$y."\n";
  a($y);
}

try {
  b(-10);
  echo('OK! No exception caught.'."\n\n");
} catch (Exception $e) {
  echo 'Caught exception: ',  $e->getMessage(), "\n\n";
}

try {
  b(10);
  echo('OK! No exception caught.'."\n\n");
} catch (Exception $e) {
  echo 'Caught exception: ',  $e->getMessage(), "\n\n";
}

// Continue execution
echo 'Hello World';
?>

Actual result:
--------------
<?php
try {
   $error = 'Always throw this error';
   throw new Exception($error);

   // Code following an exception is not executed.
   echo 'Never executed';

} catch (Exception $e) {
   echo 'Caught exception: ',  $e->getMessage(), "\n";
}

// Continue execution
echo 'Hello World';
?>