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WCRTOMB(3) Linux Programmer's Manual WCRTOMB(3)

NAME

     wcrtomb - convert a wide character to a multibyte sequence

SYNOPSIS

     #include <wchar.h>

     size_t wcrtomb(char *s, wchar_t wc, mbstate_t *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 con-
     verts  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 represen-
     tation, 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 rep-
     resented 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 |
     +----------+---------------+----------------------------+

CONFORMING TO

     POSIX.1-2001, POSIX.1-2008, C99.

NOTES

     The behavior of wcrtomb() depends on the LC_CTYPE category of the  cur-
     rent locale.

     Passing NULL as ps is not multithread safe.