function.preg-match does not reference that input string length is limited to pcre.backtrack_limit

[mvl22]

From manual page: https://php.net/function.preg-match

If the $subject parameter is too long, this function will fail. It is subject to pcre.backtrack_limit, but this is not referenced on the page.

It would be useful if the subject parameter documented this explicitly.

See another user who ran into the same mysterious problem: https://stackoverflow.com/questions/4180910/#comment92414114_4180924