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MBTOWC(P)			    POSIX Programmer's Manual				MBTOWC(P)

NAME
       mbtowc - convert a character to a wide-character code

SYNOPSIS
       #include <stdlib.h>

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

DESCRIPTION
       If  s  is not a null pointer, mbtowc() shall determine the number of bytes that constitute
       the character pointed to by s. It shall then determine the  wide-character  code  for  the
       value of type wchar_t that corresponds to that character. (The value of the wide-character
       code corresponding to the null byte is 0.) If the character is valid and pwc is not a null
       pointer, mbtowc() shall store the wide-character code in the object pointed to by pwc.

       The  behavior of this function is affected by the LC_CTYPE category of the current locale.
       For a state-dependent encoding, this function is placed into its initial state by  a  call
       for  which  its character pointer argument, s, is a null pointer.  Subsequent calls with s
       as other than a null pointer shall cause the internal state of the function to be  altered
       as  necessary.  A call with s as a null pointer shall cause this function to return a non-
       zero value if encodings have state dependency, and  0  otherwise.  If  the  implementation
       employs	special  bytes	to change the shift state, these bytes shall not produce separate
       wide-character codes, but shall be  grouped  with  an  adjacent	character.  Changing  the
       LC_CTYPE  category  causes  the	shift state of this function to be unspecified. At most n
       bytes of the array pointed to by s shall be examined.

       The  implementation  shall  behave  as  if  no  function  defined  in   this   volume   of
       IEEE Std 1003.1-2001 calls mbtowc().

RETURN VALUE
       If  s  is a null pointer, mbtowc() shall return a non-zero or 0 value, if character encod-
       ings, respectively, do or do not have state-dependent  encodings.  If  s  is  not  a  null
       pointer, mbtowc() shall either return 0 (if s points to the null byte), or return the num-
       ber of bytes that constitute the converted character (if the next n or fewer bytes form	a
       valid character), or return -1	 and may set errno to indicate the error  (if they do not
       form a valid character).

       In no case shall the value returned be greater than n or the  value  of	the  {MB_CUR_MAX}
       macro.

ERRORS
       The mbtowc() function may fail if:

       EILSEQ Invalid character sequence is detected.

       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       None.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       mblen()	 ,  mbstowcs()	,  wctomb()  ,	wcstombs()  ,  the  Base  Definitions  volume  of
       IEEE Std 1003.1-2001, <stdlib.h>

COPYRIGHT
       Portions of this text are reprinted and	reproduced  in	electronic  form  from	IEEE  Std
       1003.1,	2003  Edition,	Standard  for Information Technology -- Portable Operating System
       Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003  by
       the  Institute  of  Electrical  and  Electronics Engineers, Inc and The Open Group. In the
       event of any discrepancy between this version and the original IEEE  and  The  Open  Group
       Standard, the original IEEE and The Open Group Standard is the referee document. The orig-
       inal Standard can be obtained online at http://www.opengroup.org/unix/online.html .

IEEE/The Open Group			       2003					MBTOWC(P)
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