mbtowc

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



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. If 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 char-
       acter, 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 func-
       tion, 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  fail-
       ure.

       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.



GNU                               2001-07-04                         MBTOWC(3)