28 Regular expressions library [re]

28.8 Class template basic_­regex [re.regex]

28.8.3 Constant operations [re.regex.operations]

unsigned mark_count() const;
Effects: Returns the number of marked sub-expressions within the regular expression.
flag_type flags() const;
Effects: Returns a copy of the regular expression syntax flags that were passed to the object's constructor or to the last call to assign.