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 known only to the mbtowc() function.  If s
       does  not  point  to a null byte ('\0'), 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()  func‐
       tion  behaves as above, except that it does not store the converted wide character in mem‐
       ory.

       A third case is when s is NULL.  In this case, pwc and n are ignored.  The mbtowc()  func‐
       tion  resets  the  shift  state,  only  known  to this function, to the initial state, and
       returns nonzero if the encoding has nontrivial 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 nonzero if the encoding has  nontrivial  shift
       state, or zero if the encoding is stateless.

CONFORMING TO
       C99.

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

       This  function  is not multithread safe.  The function mbrtowc(3) provides a better inter‐
       face to the same functionality.

SEE ALSO
       MB_CUR_MAX(3), mblen(3), mbrtowc(3), mbstowcs(3), wctomb(3), wcstombs(3)

COLOPHON
       This page is part of release 3.74 of the Linux man-pages project.  A  description  of  the
       project,  information  about  reporting  bugs, and the latest version of this page, can be
       found at http://www.kernel.org/doc/man-pages/.



GNU                                         2014-03-18                                  MBTOWC(3)