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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'\0').  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 ('\0'), 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.

ATTRIBUTES

       For an explanation of the terms used in this section, see attributes(7).

       ┌─────────────────────────┬───────────────┬────────────────┐
       │InterfaceAttributeValue          │
       ├─────────────────────────┼───────────────┼────────────────┤
       │wprintf(), fwprintf(),   │ Thread safety │ MT-Safe locale │
       │swprintf(), vwprintf(),  │               │                │
       │vfwprintf(), vswprintf() │               │                │
       └─────────────────────────┴───────────────┴────────────────┘

CONFORMING TO

       POSIX.1-2001, POSIX.1-2008, 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

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