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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 ||
           _ISOC95_SOURCE /* Since glibc 2.12 */ ||
           _POSIX_C_SOURCE >= 200112L;
           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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       project,  and information about reporting bugs, can be found at http://man7.org/linux/man-
       pages/.