std::mbsinit - cppreference.com (original) (raw)
If ps is not a null pointer, the mbsinit function determines whether the pointed-to std::mbstate_t object describes the initial conversion state.
[edit] 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.
[edit] Parameters
[edit] Return value
0 if ps is not a null pointer and does not represent the initial conversion state, nonzero value otherwise.
[edit] Example
#include #include #include #include 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