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NAME

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

SYNOPSIS

       #include <stdio.h>
       #include <wchar.h>

       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
       information.

       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
              converted  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
              written up to (but not  including)  the  terminating  null  wide
              character.  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
              terminating  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 character.  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
       platform- and locale-dependent.  (The glibc represents wide  characters
       using  their  Unicode (ISO-10646) code point, but other platforms don’t
       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

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