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std::mbstowcs(3) C++ Standard Libary std::mbstowcs(3) NAME std::mbstowcs - std::mbstowcs Synopsis Defined in header <cstdlib> std::size_t mbstowcs( wchar_t* dst, const char* src, std::size_t len); Converts a multibyte character string from the array whose first el- ement is pointed to by src to its wide character representation. Converted characters are stored in the successive elements of the array pointed to by dst. No more than len wide characters are written to the destination array. Each character is converted as if by a call to std::mbtowc, except that the mbtowc conversion state is unaffected. The conversion stops if: * The multibyte null character was converted and stored. * An invalid (in the current C locale) multibyte character was en- countered. * The next wide 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::mbsrtowcs should be used in such cases. POSIX specifies a common extension: if dst is a null pointer, this function returns the number of wide characters that would be written to dst, if con- verted. Similar behavior is standard for std::mbsrtowcs. Parameters dst - pointer to wide character array where the wide string will be stored src - pointer to the first element of a null-terminated multibyte string to convert len - number of wide characters available in the array pointed to by dst Return value On success, returns the number of wide characters, excluding the terminating L'\0', written to the destination array. On conversion error (if invalid multibyte character was encoun- tered), returns 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"); std::wcout.imbue(std::locale("en_US.utf8")); const char* mbstr = "z\u00df\u6c34\U0001f34c"; // or u8"z" // or "\x7a\xc3\x9f\xe6\xb0\xb4\xf0\x9f\x8d\x8c"; wchar_t wstr[5]; std::mbstowcs(wstr, mbstr, 5); std::wcout << "wide string: " << wstr << '\n'; } Output: wide string: z See also mbsrtowcs converts a narrow multibyte character string to wide string, given state (function) wcstombs converts a wide string to narrow multibyte character string (function) do_in converts a string from externT to internT, such as when reading from file [virtual] (virtual protected member function of std::codecvt<In- ternT,ExternT,State>) http://cppreference.com 2022.07.31 std::mbstowcs(3)
NAME | Synopsis | Notes | Parameters | Return value | Example | Output: | See also
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