std::mbrtoc32 (3) - Linux Manuals
Defined in header <cuchar>
std::size_t mbrtoc32( char32_t* pc32,
const char* s, (since C++11)
std::mbstate_t* ps );
Converts a narrow multibyte character to its UTF-32 character representation.
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 32-bit character and stores it in *pc32 (if pc32 is not null).
If the multibyte character in *s corresponds to a multi-char32_t sequence (not possible with UTF-32), then after the first call to this function, *ps is updated in such a way that the next calls to mbrtoc32 will write out the additional char32_t, without considering *s.
If s is a null pointer, the values of n and pc32 are ignored and the call is equivalent to std::mbrtoc32(NULL, "", 1, ps).
If the wide character produced is the null character, the conversion state *ps represents the initial shift state.
The multibyte encoding used by this function is specified by the currently active C locale.
pc32 - pointer to the location where the resulting 32-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
The first of the following that applies:
* 0 if the character converted from s (and stored in *pc32 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 char32_t from a multi-char32_t character has now been written to *pc32. 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 *pc32.
* -1 if encoding error occurs. Nothing is written to *pc32, the value EILSEQ is stored in errno and the value of *ps is unspecified.
// Run this code
c32rtomb convert a 32-bit wide character to narrow multibyte string
do_in converts a string from externT to internT, such as when reading from file