std::mbrtoc8

 

C++

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Technical Specifications

 

Strings library

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Classes

basic_string

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char_traits

 

Null-terminated multibyte strings

Wide/multibyte conversions
mbsinit
mbtowc mbstowcs btowc mbrtowc mbsrtowcs mbrtoc8 (C++20) mbrtoc16 (C++11) mbrtoc32 (C++11) mblen	wctomb wcstombs wctob wcrtomb wcsrtombs c8rtomb (C++20) c16rtomb (C++11) c32rtomb (C++11) mbrlen
Types
mbstate_t

 

Defined in header <cuchar>
std::size_t mbrtoc8( char8_t* pc8,                      const char* s,                      std::size_t n,                      std::mbstate_t* ps );		(since C++20)

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(NULL, "", 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
• -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.
• -2 if the next n bytes constitute an incomplete, but so far valid, multibyte character. Nothing is written to *pc8.
• -1 if encoding error occurs. Nothing is written to *pc8, the value EILSEQ is stored in errno and the value of *ps is unspecified.

See also

c8rtomb (C++20)

converts UTF-8 string to narrow multibyte encoding (function)