"in the astChrSub prologue. Note, this function differs from astChrSub in that any equals signs (=) in the regular expression are treated literally.
". A NULL pointer is returned if no matches were found. A NULL pointer may be supplied if the location of the last matching character is not needed.
"elements. Each element is a pointer to a dynamically allocated character string containing a sub-string extracted from the supplied string. The array itself, and the strings within it, should all be freed using astFree when no longer needed.
If a parenthesised sub-string in the regular expression is matched by
more than one sub-string within the test string, then only the first is
returned. To return multiple matches, the regular expression should include
multiple copies of the parenthesised sub-string (for instance, separated by
the intervening string is immaterial).
A NULL pointer is returned if this function is invoked with the global error status set or if it should fail for any reason, or if the supplied string contains no words.