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std::wcstombs(3) C++ Standard Libary std::wcstombs(3) NAME std::wcstombs - std::wcstombs Synopsis Defined in header <cstdlib> std::size_t wcstombs( char* dst, const wchar_t* src, std::size_t len); Converts a sequence of wide characters from the array whose first element is pointed to by src to its narrow multibyte representation that begins in the initial shift state. Converted characters are stored in the successive elements of the char array pointed to by dst. No more than len bytes are written to the desti- nation array. Each character is converted as if by a call to std::wctomb, except that the wctomb's conversion state is unaffected. The conversion stops if: * The null character was converted and stored. * A wchar_t was found that does not correspond to a valid charac- ter in the current C locale. * The next multibyte character to be stored would exceed len. Notes In most implementations, this function updates a global static ob- ject of type std::mbstate_t as it processes through the string, and cannot be called simultaneously by two threads, std::wcsrtombs should be used in such cases. POSIX specifies a common extension: if dst is a null pointer, this function returns the number of bytes that would be written to dst, if converted. Sim- ilar behavior is standard for std::wcsrtombs. Parameters dst - pointer to narrow character array where the multibyte charac- ter will be stored src - pointer to the first element of a null-terminated wide string to convert len - number of byte available in the array pointed to by dst Return value On success, returns the number of bytes (including any shift se- quences, but excluding the terminating '\0') written to the character array whose first element is pointed to by dst. On conversion error (if invalid wide character was encountered), re- turns static_cast<std::size_t>(-1). Example // Run this code #include <iostream> #include <clocale> #include <cstdlib> int main() { std::setlocale(LC_ALL, "en_US.utf8"); // UTF-8 narrow multibyte encoding const wchar_t* wstr = L"z\u00df\u6c34\U0001d10b"; // or L"z" char mbstr[11]; std::wcstombs(mbstr, wstr, 11); std::cout << "multibyte string: " << mbstr << '\n'; } Output: multibyte string: z See also wcsrtombs converts a wide string to narrow multibyte character string, given state (function) mbstowcs converts a narrow multibyte character string to wide string (function) do_out converts a string from internT to externT, such as when writing to file [virtual] (virtual protected member function of std::codecvt<In- ternT,ExternT,State>) http://cppreference.com 2022.07.31 std::wcstombs(3)
NAME | Synopsis | Notes | Parameters | Return value | Example | Output: | See also
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