char_traits (3C++std) - Tru64 UNIX
Standard C++ LibraryCopyright 1996, Rogue Wave Software, Inc. NAME
char_traits_ - A traits class providing types and operations to the
basic_string container and iostream classes.
SYNOPSIS
#include <string>
template <class charT> struct char_traits
struct char_traits<char>; .
struct char_traits<wchar_t>;
DESCRIPTION
The char_traits struct provides elementary operations to instantiations of
basic_string and iostream classes. As with all traits classes, char_traits
is used to specialize the behavior of a template. In this case, the traits
class provides functions based on character type to the basic_string
template and to the templates that are part of the iostreams library.
Specializations of char_traits are provided for char and wchar_t. These
are used to define, respectively, string and wstring, cout and wcout, etc.
INTERFACE
template <class charT> struct char_traits .
{
typedef charT char_type;
typedef int int_type;
typedef streampos pos_type;
typedef streamoff off_type;
typedef mbstate_t state_type;
static void assign (char_type&, const char_type&);
static char_type* assign (char_type*, size_t, const char_type&);
static bool eq (const char_type&, const char_type&);
static bool lt (const char_type&, const char_type&);
static int compare (const char_type*, const char_type*, size_t);
static size_t length (const char_type * s);
static const char_type*
find (const char_type*, int, const char_type&);
static char_type* move (char_type*, const char_type*, size_t);
static char_type* copy (char_type*, const char_type*, size_t);
static int_type not_eof(const int_type& c);
static char_type to_char_type(const int_type& c);
static int_type to_int_type(const char_type& c);
static bool eq_int_type(const int_type& c1, const int_type& c2);
static int_type eof();
};
TYPE
char_type
The basic character type. Same as the template parameter.
int_type
A type that can represent all the character values of char_type as well
as and end of file value.
pos_type
A type used to represent a position within a stream buffer.
off_type
A type used to represent an offset to a position within a stream
buffer.
state_type
A type used to represent the state class or type that is applied to the
codecvt facet. This type is only relevant for streams with a underlying
character type that is multi-byte.
OPERATIONS
static
void assign(char_type& c1, const char_type& c2)
Assigns one character value to another. The value of c2 is assigned to
c1.
static
char_type* assign(char_type* s, size_t n, const char_type& a)
Assigns one character value to n elements of a character array. The
value of a is assigned to n elements of s.
static
bool eq(const char_type& c1, const char_type& c2)
Returns true if c1 equals c2.
static
bool lt(const char_type& c1, const char_type& c2)
Returns true if c1 is less than c2.
static
int compare(const char_type* s1, const char_type* s2,
size_t n)
Compares n values from s1 with n values from s2. Return 1 if
s1 is greater than s2, -1 if s1 is less than s2, or 0 if they
are equal.
static
size_t length(const char_type * s)
Returns the length of the null terminated character array s. The eos
terminator is not counted.
static
const char_type* find(const char_type* s, int n,
const char_type& a)
Looks for the value of a in s. Only n elements of s are examined.
Returns a pointer to the matched element if one is found.
Otherwise returns s + n.
static
char_type* move(char_type* s1, const char_type* s2, size_t n)
Moves n values from s1 to s2. The ranges of (s1,s1+n) and (s2,s2+n) may
overlap.
static
char_type* copy(char_type* s1, const char_type* s2, size_t n)
Copy n values from s1 to s2. The ranges of (s1,s1+n) and (s2,s2+n) may
not overlap.
static
int_type not_eof(const int_type& c)
Returns c if c is not equal to eof(), otherwise returns 0.
static
int_type to_char_type(const int_type& c)
Returns the char_type representation of c. This value may not be useful
if no such representation exists.
static
int_type to_int_type(const char_type& c)
Returns the int_type representation of c.
static
bool eq_int_type(const int_type& c1, const int_type& c2)
Returns true if c1 equals c2..
static
int_type eof()
Returns EOF.
SEE ALSO
basic_string, traits, basic_ostream, basic_istream, cout, cin, wcout, wcin
STANDARDS CONFORMANCE
ANSI X3J16/ISO WG21 Joint C++ Committee
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