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()  function behaves as above, except 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 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.

ATTRIBUTES

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

   
   Interface  Attribute      Value          
   
   mbtowc()   Thread safety  MT-Unsafe race 
   

CONFORMING TO

   POSIX.1-2001, POSIX.1-2008, 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 interface to the same functionality.

SEE ALSO

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

COLOPHON

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