MySQL+Security: Escape MySQL queries preventing injections

cleanQuery.php

<?php
/** Function to sanitize values received from the form. Prevents SQL injection */
function clean($str) {
	$str = @trim($str);
	if(get_magic_quotes_gpc()) {
		$str = stripslashes($str);
	}
	return mysql_real_escape_string($str);
}
?>

escapeQuery.php

<?php
/** To escape the database queries for avoiding SQL injection attacks */
function escape($query)
{
	if (!get_magic_quotes_gpc()) {
	    $xquery = mysql_real_escape_string($query);
	    /// If there's no mysql connection, then the xquery will be false
	    if($xquery===false)
	    {
             /*Connect to Database*/
	     connect();
	     return escape($query);
	    }
	    else return $xquery;
	}
	return $query;
}
?>