is works with both matching functions. By default,
the called function displays the callout number, the start and current
positions in the text at the callout time, and the next pattern item to be
tested. For example, the output
<pre>
  ---&#62;pqrabcdef
    0    ^  ^     \d
</pre>
indicates that callout number 0 occurred for a match attempt starting at the
fourth character of the subject string, when the pointer was at the seventh
character of the data, and when the next pattern item was \d. Just one
circu