NAME¶

std::mbrtoc8 - std::mbrtoc8

Synopsis¶

Defined in header <cuchar>
std::size_t mbrtoc8( char8_t* pc8,

const char* s, (since C++20)
std::size_t n,

std::mbstate_t* ps );

Converts a narrow multibyte character to UTF-8 encoding.

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 UTF-8 and stores the first UTF-8 code unit in *pc8 (if pc8 is
not null).

If UTF-8 encoding of the multibyte character in *s consists of more than one UTF-8
code unit, then after the first call to this function, *ps is updated in such a way
that the next call to mbrtoc8 will write out the additional UTF-8 code units,
without considering *s.

If s is a null pointer, the values of n and pc8 are ignored and the call is
equivalent to std::mbrtoc8(nullptr, "", 1, ps).

If UTF-8 code unit produced is u8'\0', the conversion state *ps represents the
initial shift state.

The multibyte encoding used by this function is specified by the currently active C
locale.

Parameters¶

pc8 - pointer to the location where the resulting UTF-8 code units 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

Return value¶

The first of the following that applies:

* 0 if the character converted from s (and stored in *pc8 if non-null) was
the null character
* the number of bytes [1...n] of the multibyte character successfully converted
from s
* static_cast<std::size_t>(-3) if the next UTF-8 code unit from a character whose
encoding consists of multiple code units has now been written to *pc8. No bytes
are processed from the input in this case.
* static_cast<std::size_t>(-2) if the next n bytes constitute an incomplete, but
so far valid, multibyte character. Nothing is written to *pc8.
* static_cast<std::size_t>(-1) if encoding error occurs. Nothing is written to
*pc8, the value EILSEQ is stored in errno and the value of *ps is unspecified.

Example¶

This section is incomplete
Reason: no example

See also¶

c8rtomb converts UTF-8 string to narrow multibyte encoding
(C++20) (function)