<?php

function logit (string $message)
{
   echo "i´m here ";
}

// ignore direkt errors from mysql for this test
mysql_query("foobar");

logit(mysql_error());
?>

brings this errors (mysql_query expected, Catchable NOT)

Warning: mysql_query() [function.mysql-query]: Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2) in /hermes/web06/b2204/pow.badhallnet/ffneu/htdocs/test.php on line 11

Warning: mysql_query() [function.mysql-query]: A link to the server could not be established in /hermes/web06/b2204/pow.badhallnet/ffneu/htdocs/test.php on line 11

Catchable fatal error: Argument 1 passed to logit() must be an instance of string, string given, called in /hermes/web06/b2204/pow.badhallnet/ffneu/htdocs/test.php on line 13 and defined in /hermes/web06/b2204/pow.badhallnet/ffneu/htdocs/test.php on line 3