Defined in header <cwchar> | ||
---|---|---|
std::size_t mbrtowc( wchar_t* pwc, const char* s, std::size_t n, std::mbstate_t* ps ); |
Converts a narrow multibyte character to a wide character.
If s
is not a null pointer, inspects at most n
bytes of the multibyte character string, beginning with the byte pointed to by s
to determine the number of bytes necessary to complete the next multibyte character (including any shift sequences). If the function determines that the next multibyte character in s
is complete and valid, converts it to the corresponding wide character and stores it in *pwc
(if pwc
is not null).
If s
is a null pointer, the values of n
and pwc
are ignored and call is equivalent to std::mbrtowc(NULL, "", 1, ps)
.
If the wide character produced is the null character, the conversion state stored in *ps
is the initial shift state.
pwc | - | pointer to the location where the resulting wide character will be written |
s | - | pointer to the multibyte character string used as input |
n | - | limit on the number of bytes in s that can be examined |
ps | - | pointer to the conversion state used when interpreting the multibyte string |
The first of the following that applies:
â0â
if the character converted from s
(and stored in pwc
if non-null) was the null character [1...n]
of the multibyte character successfully converted from s
static_cast<std::size_t>(-2)
if the next n
bytes constitute an incomplete, but so far valid, multibyte character. Nothing is written to *pwc
. static_cast<std::size_t>(-1)
if encoding error occurs. Nothing is written to *pwc
, the value EILSEQ
is stored in errno
and the value of *ps
is left unspecified. #include <iostream> #include <clocale> #include <cstring> #include <cwchar> void print_mb(const char* ptr) { std::mbstate_t state = std::mbstate_t(); // initial state const char* end = ptr + std::strlen(ptr); int len; wchar_t wc; while((len = std::mbrtowc(&wc, ptr, end-ptr, &state)) > 0) { std::wcout << "Next " << len << " bytes are the character " << wc << '\n'; ptr += len; } } int main() { std::setlocale(LC_ALL, "en_US.utf8"); // UTF-8 narrow multibyte encoding const char* str = u8"z\u00df\u6c34\U0001d10b"; // or u8"zĂć°´đ" // or "\x7a\xc3\x9f\xe6\xb0\xb4\xf0\x9d\x84\x8b"; print_mb(str); }
Output:
Next 1 bytes are the character z Next 2 bytes are the character Ă Next 3 bytes are the character ć°´ Next 4 bytes are the character đ
converts the next multibyte character to wide character (function) |
|
converts a wide character to its multibyte representation, given state (function) |
|
[virtual] | converts a string from externT to internT, such as when reading from file (virtual protected member function of std::codecvt<InternT,ExternT,State> ) |
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