Reference
C Library
IOstream Library
Strings library
STL Containers
STL Algorithms
Miscellaneous

Miscellaneous
complex
exception
functional
iterator
limits
locale
memory
new
numeric
stdexcept
typeinfo
utility
valarray

locale
has_facet
isalnum
isalpha
iscntrl
isdigit
isgraph
islower
isprint
ispunct
isspace
isupper
isxdigit
locale
tolower
toupper
use_facet
standard facets:
codecvt
codecvt_base
codecvt_byname
collate
collate_byname
ctype
ctype_base
ctype_byname
messages
messages_base
messages_byname
moneypunct
moneypunct_byname
money_base
money_get
money_put
numpunct
numpunct_byname
num_get
num_put
time_base
time_get
time_get_byname
time_put
time_put_byname

ctype_base

class

<locale>

class ctype_base;

Base class for ctype

This is not a facet type, but the base class that defines the mask bitmask member type to be inherited by facet class ctype:

1 2 3 4 5 6 7 8

class ctype_base {
public:
  enum mask {    // numeric values only as example of possible bitmask values:
    space=1<<0, print=1<<1, cntrl=1<<2, upper=1<<3, lower=1<<4,
    alpha=1<<5, digit=1<<6, punct=1<<7, xdigit=1<<8,
    alnum=alpha|digit, graph=alnum|punct
  };
};

See ctype::mask for a description of the meaning of each enum label in the ctype locale facet.