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FWPRINTF(3P)			    POSIX Programmer's Manual			     FWPRINTF(3P)

PROLOG
       This  manual  page  is part of the POSIX Programmer's Manual.  The Linux implementation of
       this interface may differ (consult the corresponding Linux  manual  page  for  details  of
       Linux behavior), or the interface may not be implemented on Linux.

NAME
       fwprintf, swprintf, wprintf - print formatted wide-character output

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

       int fwprintf(FILE *restrict stream, const wchar_t *restrict format, ...);
       int swprintf(wchar_t *restrict ws, size_t n,
	      const wchar_t *restrict format, ...);
       int wprintf(const wchar_t *restrict format, ...);

DESCRIPTION
       The fwprintf() function shall place output on the named output stream. The wprintf() func-
       tion shall place output on the standard output  stream  stdout.	The  swprintf()  function
       shall  place  output  followed  by  the null wide character in consecutive wide characters
       starting at *ws; no more than n wide characters shall be written, including a  terminating
       null wide character, which is always added (unless n is zero).

       Each  of  these	functions shall convert, format, and print its arguments under control of
       the format wide-character string.  The format is composed  of  zero  or	more  directives:
       ordinary  wide-characters,  which  are  simply copied to the output stream, and conversion
       specifications, each of which results in the fetching  of  zero	or  more  arguments.  The
       results	are  undefined if there are insufficient arguments for the format.  If the format
       is exhausted while arguments remain, the excess arguments are evaluated but are	otherwise
       ignored.

       Conversions  can  be  applied  to  the nth argument after the format in the argument list,
       rather than to the next unused argument. In this case, the conversion specifier wide char-
       acter % (see below) is replaced by the sequence "%n$", where n is a decimal integer in the
       range [1,{NL_ARGMAX}], giving the position of the argument in the argument list. This fea-
       ture provides for the definition of format wide-character strings that select arguments in
       an order appropriate to specific languages (see the EXAMPLES section).

       The format can contain either numbered argument specifications (that is, "%n$" and "*m$"),
       or  unnumbered  argument  conversion specifications (that is, % and * ), but not both. The
       only exception to this is that %% can be mixed with the "%n$" form. The results of  mixing
       numbered  and  unnumbered  argument  specifications  in a format wide-character string are
       undefined. When numbered argument specifications are used,  specifying  the  Nth  argument
       requires  that  all the leading arguments, from the first to the (N-1)th, are specified in
       the format wide-character string.

       In format wide-character strings containing the "%n$" form  of  conversion  specification,
       numbered  arguments  in the argument list can be referenced from the format wide-character
       string as many times as required.

       In format wide-character strings containing the % form of conversion  specification,  each
       argument in the argument list shall be used exactly once.

       All  forms  of the fwprintf() function allow for the insertion of a locale-dependent radix
       character in the output string, output as a wide-character value. The radix  character  is
       defined	in  the  program's  locale  (category  LC_NUMERIC ). In the POSIX locale, or in a
       locale where the radix character is not defined, the radix character shall  default  to	a
       period ( '.' ).

       Each  conversion  specification	is  introduced by the '%' wide character  or by the wide-
       character sequence "%n$", after which the following appear in sequence:

	* Zero or more flags (in any order), which modify the meaning of the conversion  specifi-
	  cation.

	* An  optional minimum field width. If the converted value has fewer wide characters than
	  the field width, it shall be padded with spaces by default on the  left;  it	shall  be
	  padded  on the right, if the left-adjustment flag ( '-' ), described below, is given to
	  the field width. The field width takes the form of  an  asterisk  (  '*'  ),	described
	  below, or a decimal integer.

	* An  optional	precision that gives the minimum number of digits to appear for the d, i,
	  o, u, x, and X conversion specifiers; the number of digits to appear	after  the  radix
	  character  for  the  a,  A, e, E, f, and F conversion specifiers; the maximum number of
	  significant digits for the g and G conversion specifiers; or the maximum number of wide
	  characters  to  be  printed from a string in the s conversion specifiers. The precision
	  takes the form of a period ( '.' ) followed either by an asterisk (  '*'  ),	described
	  below,  or an optional decimal digit string, where a null digit string is treated as 0.
	  If a precision appears with any other conversion wide character, the behavior is  unde-
	  fined.

	* An optional length modifier that specifies the size of the argument.

	* A  conversion  specifier  wide  character  that  indicates the type of conversion to be
	  applied.

       A field width, or precision, or both, may be indicated by an asterisk (	'*'  ).  In  this
       case  an  argument  of  type int supplies the field width or precision. Applications shall
       ensure that arguments specifying field width, or precision, or both appear in  that  order
       before  the  argument,  if any, to be converted.  A negative field width is taken as a '-'
       flag followed by a positive field width. A negative precision is taken as if the precision
       were  omitted.  In format wide-character strings containing the "%n$" form of a conversion
       specification, a field width or precision may be indicated by the sequence "*m$", where	m
       is a decimal integer in the range [1,{NL_ARGMAX}] giving the position in the argument list
       (after the format argument) of an integer argument containing the field	width  or  preci-
       sion, for example:

	      wprintf(L"%1$d:%2$.*3$d:%4$.*3$d\n", hour, min, precision, sec);

       The flag wide characters and their meanings are:

       '      The integer portion of the result of a decimal conversion ( %i, %d, %u, %f, %F, %g,
	      or %G ) shall be formatted with thousands' grouping wide characters. For other con-
	      versions, the behavior is undefined. The numeric grouping wide character is used.

       -      The result of the conversion shall be left-justified within the field.  The conver-
	      sion shall be right-justified if this flag is not specified.

       +      The result of a signed conversion shall always begin with a sign ( '+'  or  '-'  ).
	      The  conversion  shall begin with a sign only when a negative value is converted if
	      this flag is not specified.

       <space>
	      If the first wide character of a signed conversion is not a sign, or  if	a  signed
	      conversion  results  in  no  wide  characters,  a  <space> shall be prefixed to the
	      result. This means that if the <space> and '+' flags both appear, the <space>  flag
	      shall be ignored.

       #      Specifies  that the value is to be converted to an alternative form.  For o conver-
	      sion, it increases the precision (if necessary) to force the  first  digit  of  the
	      result  to  be 0. For x or X conversion specifiers, a non-zero result shall have 0x
	      (or 0X) prefixed to it. For a, A, e, E, f, F, g, and G conversion  specifiers,  the
	      result shall always contain a radix character, even if no digits follow it. Without
	      this flag, a radix character appears in the result of these conversions only  if	a
	      digit  follows  it.  For g and G conversion specifiers, trailing zeros shall not be
	      removed from the result as they normally are. For other conversion specifiers,  the
	      behavior is undefined.

       0      For  d,  i,  o,  u, x, X, a, A, e, E, f, F, g, and G conversion specifiers, leading
	      zeros (following any indication of sign or base) are  used  to  pad  to  the  field
	      width; no space padding is performed. If the '0' and '-' flags both appear, the '0'
	      flag shall be ignored. For d, i, o, u, x, and X conversion specifiers, if a  preci-
	      sion  is	specified,  the  '0'  flag shall be ignored. If the '0' and '" flags both
	      appear, the grouping wide characters are inserted before zero  padding.  For  other
	      conversions, the behavior is undefined.

       The length modifiers and their meanings are:

       hh     Specifies  that  a  following d, i, o, u, x, or X conversion specifier applies to a
	      signed char or unsigned char argument (the argument will have been promoted accord-
	      ing  to  the integer promotions, but its value shall be converted to signed char or
	      unsigned char before printing); or that a following n conversion specifier  applies
	      to a pointer to a signed char argument.

       h      Specifies  that  a  following d, i, o, u, x, or X conversion specifier applies to a
	      short or unsigned short argument (the argument will have been promoted according to
	      the integer promotions, but its value shall be converted to short or unsigned short
	      before printing); or that a following n conversion specifier applies to  a  pointer
	      to a short argument.

       l (ell)
	      Specifies  that  a  following d, i, o, u, x, or X conversion specifier applies to a
	      long or unsigned long argument; that a following n conversion specifier applies  to
	      a  pointer to a long argument; that a following c conversion specifier applies to a
	      wint_t argument; that a following s conversion specifier applies to a pointer to	a
	      wchar_t argument; or has no effect on a following a, A, e, E, f, F, g, or G conver-
	      sion specifier.

       ll (ell-ell)

	      Specifies that a following d, i, o, u, x, or X conversion specifier  applies  to	a
	      long  long  or unsigned long long argument; or that a following n conversion speci-
	      fier applies to a pointer to a long long argument.

       j      Specifies that a following d, i, o, u, x, or X conversion specifier applies  to  an
	      intmax_t	or uintmax_t argument; or that a following n conversion specifier applies
	      to a pointer to an intmax_t argument.

       z      Specifies that a following d, i, o, u, x, or X conversion specifier  applies  to	a
	      size_t  or  the  corresponding  signed integer type argument; or that a following n
	      conversion specifier applies to a pointer to a signed integer type corresponding to
	      a size_t argument.

       t      Specifies  that  a  following d, i, o, u, x, or X conversion specifier applies to a
	      ptrdiff_t or the corresponding unsigned type argument; or that a following  n  con-
	      version specifier applies to a pointer to a ptrdiff_t argument.

       L      Specifies  that  a following a, A, e, E, f, F, g, or G conversion specifier applies
	      to a long double argument.

       If a length modifier appears with any conversion specifier other than as specified  above,
       the behavior is undefined.

       The conversion specifiers and their meanings are:

       d, i   The int argument shall be converted to a signed decimal in the style "[-]dddd". The
	      precision specifies the minimum number of digits to appear; if the value being con-
	      verted can be represented in fewer digits, it shall be expanded with leading zeros.
	      The default precision shall be 1. The result of converting zero  with  an  explicit
	      precision of zero shall be no wide characters.

       o      The  unsigned  argument  shall  be  converted to unsigned octal format in the style
	      "dddd" . The precision specifies the minimum number of digits  to  appear;  if  the
	      value being converted can be represented in fewer digits, it shall be expanded with
	      leading zeros. The default precision shall be 1. The result of converting zero with
	      an explicit precision of zero shall be no wide characters.

       u      The  unsigned  argument  shall be converted to unsigned decimal format in the style
	      "dddd" . The precision specifies the minimum number of digits  to  appear;  if  the
	      value being converted can be represented in fewer digits, it shall be expanded with
	      leading zeros. The default precision shall be 1. The result of converting zero with
	      an explicit precision of zero shall be no wide characters.

       x      The  unsigned  argument  shall  be  converted to unsigned hexadecimal format in the
	      style "dddd" ; the letters "abcdef" are used. The precision specifies  the  minimum
	      number  of  digits  to  appear;  if the value being converted can be represented in
	      fewer digits, it shall be expanded with leading zeros.  The default precision shall
	      be  1. The result of converting zero with an explicit precision of zero shall be no
	      wide characters.

       X      Equivalent to the x conversion specifier, except that  letters  "ABCDEF"	are  used
	      instead of "abcdef" .

       f, F   The   double  argument  shall  be  converted  to	decimal  notation  in  the  style
	      "[-]ddd.ddd", where the number of digits after the radix character shall	be  equal
	      to  the  precision specification. If the precision is missing, it shall be taken as
	      6; if the precision is explicitly zero and no '#' flag is present, no radix charac-
	      ter  shall  appear.  If  a radix character appears, at least one digit shall appear
	      before it. The value shall be rounded in an implementation-defined  manner  to  the
	      appropriate number of digits.

       A  double  argument  representing  an  infinity	shall  be  converted in one of the styles
       "[-]inf" or "[-]infinity" ; which style is implementation-defined. A double argument  rep-
       resenting  a  NaN  shall  be  converted	in  one of the styles "[-]nan" or "[-]nan(n-char-
       sequence)"; which style, and  the  meaning  of  any  n-char-sequence,  is  implementation-
       defined. The F conversion specifier produces "INF", "INFINITY", or "NAN" instead of "inf",
       "infinity", or "nan", respectively.

       e, E   The double argument shall be converted in the style  "[-]d.ddde+-dd",  where  there
	      shall be one digit before the radix character (which is non-zero if the argument is
	      non-zero) and the number of digits after it shall be equal to the precision; if the
	      precision  is  missing, it shall be taken as 6; if the precision is zero and no '#'
	      flag is present, no radix character shall appear. The value shall be rounded in  an
	      implementation-defined manner to the appropriate number of digits. The E conversion
	      wide character shall produce a number with 'E' instead of 'e' introducing the expo-
	      nent. The exponent shall always contain at least two digits.  If the value is zero,
	      the exponent shall be zero.

       A double argument representing an infinity or NaN shall be converted in the style of an	f
       or F conversion specifier.

       g, G   The  double argument shall be converted in the style f or e (or in the style F or E
	      in the case of a G conversion specifier), with the precision specifying the  number
	      of  significant  digits.	If an explicit precision is zero, it shall be taken as 1.
	      The style used depends on the value converted; style e (or E ) shall be  used  only
	      if the exponent resulting from such a conversion is less than -4 or greater than or
	      equal to the precision. Trailing zeros shall be removed from the fractional portion
	      of the result; a radix character shall appear only if it is followed by a digit.

       A  double argument representing an infinity or NaN shall be converted in the style of an f
       or F conversion specifier.

       a, A   A double argument representing a floating-point number shall be  converted  in  the
	      style  "[-]0xh.hhhhp+-d", where there shall be one hexadecimal digit (which is non-
	      zero if the argument is a normalized floating-point number and is otherwise unspec-
	      ified) before the decimal-point wide character and the number of hexadecimal digits
	      after it shall be equal to the precision; if the precision is missing and FLT_RADIX
	      is a power of 2, then the precision shall be sufficient for an exact representation
	      of the value; if the precision is missing and FLT_RADIX is not a power of  2,  then
	      the precision shall be sufficient to distinguish values of type double, except that
	      trailing zeros may be omitted; if the precision is zero and the  '#'  flag  is  not
	      specified,  no  decimal-point wide character shall appear. The letters "abcdef" are
	      used for a conversion and the letters "ABCDEF" for A conversion.	The A  conversion
	      specifier  produces a number with 'X' and 'P' instead of 'x' and 'p' . The exponent
	      shall always contain at least one digit, and only as many more digits as	necessary
	      to represent the decimal exponent of 2. If the value is zero, the exponent shall be
	      zero.

       A double argument representing an infinity or NaN shall be converted in the style of an	f
       or F conversion specifier.

       c      If  no  l (ell) qualifier is present, the int argument shall be converted to a wide
	      character as if by calling the btowc() function and the  resulting  wide	character
	      shall be written. Otherwise, the wint_t argument shall be converted to wchar_t, and
	      written.

       s      If no l (ell) qualifier is present, the application shall ensure that the  argument
	      is  a pointer to a character array containing a character sequence beginning in the
	      initial shift state.  Characters from  the  array  shall	be  converted  as  if  by
	      repeated calls to the mbrtowc() function, with the conversion state described by an
	      mbstate_t object initialized to zero before the first character is  converted,  and
	      written  up to (but not including) the terminating null wide character. If the pre-
	      cision is specified, no more than that many wide characters shall  be  written.  If
	      the  precision  is  not  specified,  or  is greater than the size of the array, the
	      application shall ensure that the array contains a null wide character.

       If an l (ell) qualifier is present, the application shall ensure that the  argument  is	a
       pointer to an array of type wchar_t. Wide characters from the array shall be written up to
       (but not including) a terminating null wide character. If no precision is specified, or is
       greater than the size of the array, the application shall ensure that the array contains a
       null wide character. If a precision is specified, no more than that many  wide  characters
       shall be written.

       p      The  application shall ensure that the argument is a pointer to void.  The value of
	      the pointer shall be converted to a sequence of printable  wide  characters  in  an
	      implementation-defined manner.

       n      The  application	shall  ensure  that  the argument is a pointer to an integer into
	      which is written the number of wide characters written to the output so far by this
	      call  to	one  of the fwprintf() functions. No argument shall be converted, but one
	      shall be consumed. If the conversion specification  includes  any  flags,  a  field
	      width, or a precision, the behavior is undefined.

       C      Equivalent to lc .

       S      Equivalent to ls .

       %      Output a '%' wide character; no argument shall be converted.  The entire conversion
	      specification shall be %% .

       If a conversion specification does not match one of the above forms, the behavior is unde-
       fined.

       In  no  case  does  a nonexistent or small field width cause truncation of a field; if the
       result of a conversion is wider than the field width, the field shall be expanded to  con-
       tain  the  conversion  result.  Characters  generated by fwprintf() and wprintf() shall be
       printed as if fputwc() had been called.

       For a and A conversions, if FLT_RADIX is not a power of 2 and the result  is  not  exactly
       representable in the given precision, the result should be one of the two adjacent numbers
       in hexadecimal floating style with the given precision, with the  extra	stipulation  that
       the error should have a correct sign for the current rounding direction.

       For  e, E, f, F, g, and G conversion specifiers, if the number of significant decimal dig-
       its is at most DECIMAL_DIG, then the result should be correctly rounded. If the number  of
       significant decimal digits is more than DECIMAL_DIG but the source value is exactly repre-
       sentable with DECIMAL_DIG digits, then the result should be an exact  representation  with
       trailing zeros. Otherwise, the source value is bounded by two adjacent decimal strings L <
       U, both having DECIMAL_DIG significant digits; the value of the resultant decimal string D
       should  satisfy	L <= D <= U, with the extra stipulation that the error should have a cor-
       rect sign for the current rounding direction.

       The st_ctime and st_mtime fields of the file shall be marked for update between	the  call
       to a successful execution of fwprintf() or wprintf() and the next successful completion of
       a call to fflush() or fclose() on the same stream, or a call to exit() or abort().

RETURN VALUE
       Upon successful completion, these functions shall return the  number  of  wide  characters
       transmitted, excluding the terminating null wide character in the case of swprintf(), or a
       negative value if an output error was encountered,  and set errno to indicate the error.

       If n or more wide characters were requested to be written, swprintf() shall return a nega-
       tive value,  and set errno to indicate the error.

ERRORS
       For  the  conditions  under  which  fwprintf()  and  wprintf() fail and may fail, refer to
       fputwc().

       In addition, all forms of fwprintf() may fail if:

       EILSEQ A wide-character code that does not  correspond  to  a  valid  character	has  been
	      detected.

       EINVAL There are insufficient arguments.

       In addition, wprintf() and fwprintf() may fail if:

       ENOMEM Insufficient storage space is available.

       The following sections are informative.

EXAMPLES
       To  print  the language-independent date and time format, the following statement could be
       used:

	      wprintf(format, weekday, month, day, hour, min);

       For American usage, format could be a pointer to the wide-character string:

	      L"%s, %s %d, %d:%.2d\n"

       producing the message:

	      Sunday, July 3, 10:02

       whereas for German usage, format could be a pointer to the wide-character string:

	      L"%1$s, %3$d. %2$s, %4$d:%5$.2d\n"

       producing the message:

	      Sonntag, 3. Juli, 10:02

APPLICATION USAGE
       None.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       btowc(), fputwc(), fwscanf(), mbrtowc(),  setlocale(),  the  Base  Definitions  volume  of
       IEEE Std 1003.1-2001, Chapter 7, Locale, <stdio.h>, <wchar.h>

COPYRIGHT
       Portions  of  this  text  are  reprinted  and  reproduced in electronic form from IEEE Std
       1003.1, 2003 Edition, Standard for Information Technology  --  Portable	Operating  System
       Interface  (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by
       the Institute of Electrical and Electronics Engineers, Inc and  The  Open  Group.  In  the
       event  of  any  discrepancy  between this version and the original IEEE and The Open Group
       Standard, the original IEEE and The Open Group Standard is the referee document. The orig-
       inal Standard can be obtained online at http://www.opengroup.org/unix/online.html .

IEEE/The Open Group			       2003				     FWPRINTF(3P)
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