C++ In a Nutshell

Name

mbstate_t type — Represents a multibyte shift state

Synopsis

typedef  . . .  mbstate_t
               

The mbstate_t type is an opaque, POD type that stores the conversion state used to convert between multibyte and wide characters. The type is implementation-defined, but it is not an array type, so an mbstate_t object can be returned from a function.

A value of 0 for an mbstate_t object corresponds to the initial shift state, although other values might also represent the initial state. Thus, to initialize an mbstate_t object, use a default constructor:

std::mbstate_t mbs = std::mbstate_t(  );

If two mbstate_t objects are identical, they represent the same shift state, but the reverse is not necessarily true.

There is no way to compare two mbstate_t objects to determine whether they represent the same state, but you can call mbsinit to determine whether a state is the initial state.

Typically, you would use an mbstate_t object by initializing it to the initial shift state, then passing it to any of the multibyte functions (such as mbrtowc) repeatedly. Each call to the multibyte function reads the shift state and uses that information for the conversion, updating the shift state depending on which multibyte characters were provided as input. You should not alter the mbstate_t object between calls to the multibyte function.

See Also

mbrlen function, mbrtowc function, mbsinit function, mbsrtowcs function, wcrtomb function, wcsrtombs function