std::mbstate_t (3) - Linux Man Pages
Defined in header <cuchar> (since C++17)
Defined in header <cwchar>
The type mbstate_t is a trivial non-array type that can represent any of the conversion states that can occur in an implementation-defined set of supported multibyte character encoding rules. Zero-initialized value of mbstate_t represents the initial conversion state, although other values of mbstate_t may exist that also represent the initial conversion state.
Possible implementation of mbstate_t is a struct type holding an array representing the incomplete multibyte character, an integer counter indicating the number of bytes in the array that have been processed, and a representation of the current shift state.
The following functions should not be called from multiple threads without synchronization with the std::mbstate_t* argument of NULL due to possible data races: std::mbrlen, std::mbrtowc, std::mbsrtowcs, std::mbtowc, std::wcrtomb, std::wcsrtombs, std::wctomb.