c32rtomb

Converts a single code point from its variable-length 32-bit wide character representation (but typically, UTF-32) to its narrow multibyte character representation.

If s is not a null pointer, the function determines the number of bytes necessary to store the multibyte character representation of c32 (including any shift sequences, and taking into account the current multibyte conversion state *ps), and stores the multibyte character representation in the character array whose first element is pointed to by s, updating *ps as necessary. At most MB_CUR_MAX bytes can be written by this function.

If s is a null pointer, the call is equivalent to c32rtomb(buf, U'\0', ps) for some internal buffer buf.

If c32 is the null wide character U'\0', a null byte is stored, preceded by any shift sequence necessary to restore the initial shift state and the conversion state parameter *ps is updated to represent the initial shift state.

If the macro __STDC_UTF_32__ is defined, the 32-bit encoding used by this function is UTF-32; otherwise, it is implementation-defined. The macro is always defined and the encoding is always UTF-32.(since C23) In any case, the multibyte character encoding used by this function is specified by the currently active C locale.