Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. — Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

Global xdigit

boost::xpressive::xdigit — Matches a hexadecimal digit character.

// In header: <boost/xpressive/regex_primitives.hpp>

unspecified xdigit;

The regex traits are used to determine which characters are hex digits. To match any character that is not a hex digit, use ~xdigit.

	Note
	xdigit is equivalent to /[[:xdigit:]]/ in perl. ~xdigit is equivalent to /[[:^xdigit:]]/ in perl.