NAME¶

std::mbsinit - std::mbsinit

Synopsis¶

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 represent 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 = "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¶

conversion state information necessary to iterate multibyte character
mbstate_t strings
(class)