locale::category

typedef int category;
static const category none, collate, ctype, monetary,
    numeric, time, messages, all;

The type is a synonym for int, so that it can represent any of the C locale categories. It can also represent a group of constants local to class locale:

• none, corresponding to none of the C categories
• collate, corresponding to the C category LC_COLLATE
• ctype, corresponding to the C category LC_CTYPE
• monetary, corresponding to the C category LC_MONETARY
• numeric, corresponding to the C category LC_NUMERIC
• time, corresponding to the C category LC_TIME
• messages, corresponding to the Posix category LC_MESSAGE
• all, corresponding to the C union of all categories LC_ALL

You can represent an arbitrary group of categories by ORing these constants, as in monetary | time.