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# std::mbrtoc16

From cppreference.com
< cpp‎ | string‎ | multibyte

Defined in header `<cuchar>` |  |
std::size_t mbrtoc16( char16_t* pc16, const char* s, std::size_t n, std::mbstate_t* ps ); |  | (since C++11)

Converts a narrow multibyte character to 16-bit character representation (typically, UTF-16).

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 16-bit character and stores it in *pc16 (if `pc16` is not null).

If the multibyte character in `*s` corresponds to a multi-char16_t sequence (e.g. a surrogate pair in UTF-16), then after the first call to this function, `*ps` is updated in such a way that the next call to `mbrtoc16` will write out the additional char16_t, without considering `*s`.

If `s` is a null pointer, the values of `n` and `pc16` are ignored and the call is equivalent to std::mbrtoc16(NULL, "", 1, ps).

If the wide character produced is the null character, the conversion state *ps represents the initial shift state.

If the macro __STDC_UTF_16__ is defined, the 16-bit encoding used by this function is UTF-16, otherwise it is implementation-defined.

### [edit] Parameters

pc16 | - | pointer to the location where the resulting 16-bit 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 object used when interpreting the multibyte string

### [edit] Return value

The first of the following that applies:

- ​0​ if the character converted from `s` (and stored in *pc16 if non-null) was the null character
- the number of bytes [1...n] of the multibyte character successfully converted from `s`
- -3 if the next char16_t from a multi-char16_t character (e.g. a surrogate pair) has now been written to *pc16. No bytes are processed from the input in this case.
- -2 if the next `n` bytes constitute an incomplete, but so far valid, multibyte character. Nothing is written to *pc16.
- -1 if encoding error occurs. Nothing is written to `*pc16`, the value EILSEQ is stored in errno and the value if *ps is unspecified.

### [edit] See also

c16rtomb (C++11) | convert a 16-bit wide character to narrow multibyte string (function) [edit]
do_in [virtual] | converts a string from externT to internT, such as when reading from file (virtual protected member function of `std::codecvt`) [edit]
C documentation for mbrtoc16

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