WPRINTF(3)		   Linux Programmers Manual		   WPRINTF(3)



NAME
       wprintf, fwprintf, swprintf, vwprintf, vfwprintf, vswprintf - formatted
       wide-character output conversion

SYNOPSIS
       #include 
       #include 

       int wprintf(const wchar_t *format, ...);
       int fwprintf(FILE *stream, const wchar_t *format, ...);
       int swprintf(wchar_t *wcs, size_t maxlen,
		    const wchar_t *format, ...);

       int vwprintf(const wchar_t *format, va_list args);
       int vfwprintf(FILE *stream, const wchar_t *format, va_list args);
       int vswprintf(wchar_t *wcs, size_t maxlen,
		     const wchar_t *format, va_list args);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       All functions shown above: _XOPEN_SOURCE >= 500 || _ISOC99_SOURCE; or
       cc -std=c99

DESCRIPTION
       The  wprintf()  family of functions is the wide-character equivalent of
       the printf(3) family of functions.  It  performs  formatted  output  of
       wide characters.

       The wprintf() and vwprintf() functions perform wide-character output to
       stdout.	stdout must not be byte oriented; see fwide(3) for more infor
       mation.

       The  fwprintf() and vfwprintf() functions perform wide-character output
       to stream.  stream must not be byte oriented;  see  fwide(3)  for  more
       information.

       The  swprintf() and vswprintf() functions perform wide-character output
       to an array of wide characters.	The programmer must ensure that  there
       is room for at least maxlen wide characters at wcs.

       These   functions  are  like  the  printf(3),  vprintf(3),  fprintf(3),
       vfprintf(3), sprintf(3), vsprintf(3) functions except for the following
       differences:

	     The format string is a wide-character string.

	     The output consists of wide characters, not bytes.

	     swprintf()  and  vswprintf()  take a maxlen argument, sprintf(3)
	      and vsprintf(3) do not.  (snprintf(3) and  vsnprintf(3)  take  a
	      maxlen  argument,  but  these  functions	do  not return -1 upon
	      buffer overflow on Linux.)

       The treatment of the conversion characters c and s is different:

       c      If no l modifier is present, the int argument is converted to  a
	      wide  character  by  a  call  to	the btowc(3) function, and the
	      resulting wide character	is  written.   If  an  l  modifier  is
	      present, the wint_t (wide character) argument is written.

       s      If  no  l  modifier  is  present:  The  const char * argument is
	      expected to be a pointer to an array of character type  (pointer
	      to a string) containing a multibyte character sequence beginning
	      in the initial shift state.  Characters from the array are  con
	      verted  to  wide	characters  (each  by a call to the mbrtowc(3)
	      function with a conversion state starting in the	initial  state
	      before the first byte).  The resulting wide characters are writ
	      ten up to (but not including) the terminating null wide  charac
	      ter.   If a precision is specified, no more wide characters than
	      the number specified  are  written.   Note  that	the  precision
	      determines the number of wide characters written, not the number
	      of bytes or screen positions.  The array must contain  a	termi
	      nating null byte, unless a precision is given and it is so small
	      that the number of converted wide characters reaches  it	before
	      the  end	of the array is reached.  If an l modifier is present:
	      The const wchar_t * argument is expected to be a pointer	to  an
	      array  of  wide  characters.  Wide characters from the array are
	      written up to (but not including) a terminating null wide  char
	      acter.   If  a  precision  is specified, no more than the number
	      specified are written.  The array  must  contain	a  terminating
	      null  wide  character,  unless  a  precision  is given and it is
	      smaller than or equal to the number of wide  characters  in  the
	      array.

RETURN VALUE
       The  functions  return the number of wide characters written, excluding
       the terminating null wide character in case of the functions swprintf()
       and vswprintf().  They return -1 when an error occurs.

CONFORMING TO
       C99.

NOTES
       The  behavior  of  wprintf() et al. depends on the LC_CTYPE category of
       the current locale.

       If the format string contains non-ASCII wide  characters,  the  program
       will only work correctly if the LC_CTYPE category of the current locale
       at run time is the same as the LC_CTYPE category of the current	locale
       at  compile  time.  This is because the wchar_t representation is plat
       form- and locale-dependent.   (The  glibc  represents  wide  characters
       using  their  Unicode (ISO-10646) code point, but other platforms dont
       do this.  Also, the use of C99 universal character names  of  the  form
       \unnnn  does  not solve this problem.)  Therefore, in internationalized
       programs, the format string should consist  of  ASCII  wide  characters
       only,  or should be constructed at run time in an internationalized way
       (e.g., using gettext(3) or iconv(3), followed by mbstowcs(3)).

SEE ALSO
       fprintf(3), fputwc(3), fwide(3), printf(3), snprintf(3).

COLOPHON
       This page is part of release 3.05 of the Linux  man-pages  project.   A
       description  of	the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.



GNU				  2007-07-26			    WPRINTF(3)