A bitmapped CInt containing options for compilation of regular expressions. Option values (and their man 3 regcomp names) are
* compBlank which is a completely zero value for all the flags. This is also the blankCompOpt value.
* compExtended (REG_EXTENDED) which can be set to use extended instead of basic regular expressions. This is set in the defaultCompOpt value.
* compNewline (REG_NEWLINE) turns on newline sensitivity: The dot (.) and inverted set [^ ] never match newline, and ^ and $ anchors do match after and before newlines. This is set in the defaultCompOpt value.
* compIgnoreCase (REG_ICASE) which can be set to match ignoring upper and lower distinctions.
* compNoSub (REG_NOSUB) which turns off all information from matching except whether a match exists.