NAME

       mbtowc - convert a multibyte sequence to a wide character

SYNOPSIS

       #include <stdlib.h>

       int mbtowc (wchar_t *pwc, const char *s, size_t n);

DESCRIPTION

       The  main  case for this function is when s is not NULL and pwc is not NULL. In this case,
       the mbtowc function inspects at most n bytes  of  the  multibyte  string  starting  at  s,
       extracts the next complete multibyte character, converts it to a wide character and stores
       it at *pwc. It updates an internal shift state only known to the  mbtowc  function.  It  s
       does  not  point to a '\0' byte, it returns the number of bytes that were consumed from s,
       otherwise it returns 0.

       If the n bytes starting at s do not contain a complete multibyte  character,  or  if  they
       contain  an  invalid  multibyte  sequence, mbtowc returns -1. This can happen even if n >=
       MB_CUR_MAX, if the multibyte string contains redundant shift sequences.

       A different case is when s is not NULL but pwc is NULL. In this case the  mbtowc  function
       behaves as above, excepts that it does not store the converted wide character in memory.

       A  third  case is when s is NULL. In this case, pwc and n are ignored. The mbtowc function
       resets the shift state, only known to this function, to the  initial  state,  and  returns
       non-zero  if  the  encoding  has  non-trivial  shift  state,  or  zero  if the encoding is
       stateless.

RETURN VALUE

       If s is not NULL, the mbtowc function returns the number of consumed bytes starting at  s,
       or 0 if s points to a null byte, or -1 upon failure.

       If  s  is NULL, the mbtowc function returns non-zero if the encoding has non-trivial shift
       state, or zero if the encoding is stateless.

CONFORMING TO

       ISO/ANSI C, UNIX98

SEE ALSO

       mbrtowc(3), mbstowcs(3), MB_CUR_MAX(3)

NOTES

       The behaviour of mbtowc depends on the LC_CTYPE category of the current locale.

       This function is not multi-thread safe. The function mbrtowc provides a  better  interface
       to the same functionality.