NAME

       wcrtomb - convert a wide character to a multibyte sequence

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

       #include <wchar.h>

       size_t wcrtomb(char *restrict s, wchar_t wc, mbstate_t *restrict ps);

DESCRIPTION

       The  main case for this function is when s is not NULL and wc is not a null wide character
       (L'\0').  In this case, the wcrtomb() function converts  the  wide  character  wc  to  its
       multibyte  representation and stores it at the beginning of the character array pointed to
       by s.  It updates  the  shift  state  *ps,  and  returns  the  length  of  said  multibyte
       representation, that is, the number of bytes written at s.

       A  different case is when s is not NULL, but wc is a null wide character (L'\0').  In this
       case, the wcrtomb() function stores at the character array  pointed  to  by  s  the  shift
       sequence  needed  to  bring  *ps  back  to the initial state, followed by a '\0' byte.  It
       updates the shift state *ps (i.e., brings it into the  initial  state),  and  returns  the
       length of the shift sequence plus one, that is, the number of bytes written at s.

       A third case is when s is NULL.  In this case, wc is ignored, and the function effectively
       returns

           wcrtomb(buf, L'\0', ps)

       where buf is an internal anonymous buffer.

       In all of the above cases, if ps is NULL, a static  anonymous  state  known  only  to  the
       wcrtomb() function is used instead.

RETURN VALUE

       The  wcrtomb()  function  returns  the  number  of bytes that have been or would have been
       written to the byte array at s.  If wc can not be  represented  as  a  multibyte  sequence
       (according to the current locale), (size_t) -1 is returned, and errno set to EILSEQ.

ATTRIBUTES

       For an explanation of the terms used in this section, see attributes(7).

       ┌────────────────────────────────────────────┬───────────────┬────────────────────────────┐
       │Interface                                   │ Attribute     │ Value                      │
       ├────────────────────────────────────────────┼───────────────┼────────────────────────────┤
       │wcrtomb()                                   │ Thread safety │ MT-Unsafe race:wcrtomb/!ps │
       └────────────────────────────────────────────┴───────────────┴────────────────────────────┘

STANDARDS

       C11, POSIX.1-2008.

HISTORY

       POSIX.1-2001, C99.

NOTES

       The behavior of wcrtomb() depends on the LC_CTYPE category of the current locale.

       Passing NULL as ps is not multithread safe.

SEE ALSO

       mbsinit(3), wcsrtombs(3)