SE THEN ...</code>.</li>
<li>**<code>PID</code>** – Contains the process ID (integer) of the current process.</li>
<li>**<code>ERR</code>** – True only while in an error handler or after an error in an <code>EVAL</code>.</li>
<li>**<code>ERRLINE</code>** – Contains the line an error last occurred on while in error handler or after an error in an <code>EVAL</code>.</li>
<li>**<code>ERR$</code>** – Contains the error message which last occurred while in error handler or after an error in an <code>EVAL