| B | |
| Backtrack [Pcre] | Backtrackused in callout functions to force backtracking. | 
| E | |
| Error [Pcre] | 
Exception indicating PCRE errors.
 | 
| R | |
| Regexp_or [Pcre] | Regexp_or (pat, error)gets raised for sub-patternpatbyregexp_orif it failed to compile. |