std::mbsinit

 

C++

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Technical Specifications

 

Strings library

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Null-terminated multibyte strings

Wide/multibyte conversions
mbsinit
mbtowc mbstowcs btowc mbrtowc mbsrtowcs mbrtoc16 (C++11) mbrtoc32 (C++11) mblen	wctomb wcstombs wctob wcrtomb wcsrtombs c16rtomb (C++11) c32rtomb (C++11) mbrlen
Types
mbstate_t

 

Defined in header <cwchar>
int mbsinit( const std::mbstate_t* ps);

If ps is not a null pointer, the mbsinit function determines whether the pointed-to std::mbstate_t object describes the initial conversion state.

Notes

Although a zero-initialized std::mbstate_t always represents the initial conversion state, there may be other values of std::mbstate_t that also represent the initial conversion state.

Parameters

ps

-

pointer to the std::mbstate_t object to examine

Return value

​0​ if ps is not a null pointer and does not reporesent the initial conversion state, nonzero value otherwise.

Example

Run this code

#include <clocale>
#include <string>
#include <iostream>
#include <cwchar>
 
int main()
{
    // allow mbrlen() to work with UTF-8 multibyte encoding
    std::setlocale(LC_ALL, "en_US.utf8");
    // UTF-8 narrow multibyte encoding
    std::string str = u8"水"; // or u8"\u6c34" or "\xe6\xb0\xb4"
    std::mbstate_t mb = std::mbstate_t();
    (void)std::mbrlen(&str[0], 1, &mb);
    if (!std::mbsinit(&mb)) {
        std::cout << "After processing the first 1 byte of " << str
                  << " the conversion state is not initial\n";
    }
 
    (void)std::mbrlen(&str[1], str.size()-1, &mb);
    if (std::mbsinit(&mb)) {
        std::cout << "After processing the remaining 2 bytes of " << str
                  << ", the conversion state is initial conversion state\n";
    }
}

Output:

After processing the first 1 byte of 水 the conversion state is not initial
After processing the remaining 2 bytes of 水, the conversion state is initial conversion state

See also

mbstate_t	conversion state information necessary to iterate multibyte character strings (class)
C documentation for mbsinit