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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 ||
           _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 (L'').  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 work correctly only 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

       This  page  is  part of release 3.65 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/.



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