Regular Expressions Regex modifiers (flags) PCRE_EXTRA modifier


Example

A PCRE modifier that causes an error if any backslash in a pattern is followed by a letter that has no special meaning. By default, a backslash followed by a letter with no special meaning is treated as a literal.

E.g.

/big\y/

will match bigy, but

/big\y/X

will throw an exception.

Inline version: (?X)