Search forward from point for regular expression REGEXP.
Find the longest match in accord with Posix regular expression rules.
Set point to the end of the occurrence found, and return point.
An optional second argument bounds the search; it is a buffer position.
The match found must not extend after that position.
Optional third argument, if t, means if fail just return nil (no error).
If not nil and not t, move to limit of search and return nil.
Optional fourth argument is repeat count--search for successive occurrences.
Search case-sensitivity is determined by the value of the variable
`case-fold-search', which see.
See also the functions `match-beginning', `match-end', `match-string',
and `replace-match'. (fn REGEXP &optional BOUND NOERROR COUNT)