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WPRINTF(3)               BSD Library Functions Manual               WPRINTF(3)

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

LIBRARY
     Standard C Library (libc, -lc)

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, ...);

     #include <stdarg.h>

     int
     vfwprintf(FILE * restrict stream, const wchar_t * restrict, va_list ap);

     int
     vswprintf(wchar_t * restrict ws, size_t n,
         const wchar_t *restrict format, va_list ap);

     int
     vwprintf(const wchar_t * restrict format, va_list ap);

DESCRIPTION
     The wprintf() family of functions produces output according to a format
     as described below.  The wprintf() and vwprintf() functions write output
     to stdout, the standard output stream; fwprintf() and vfwprintf() write
     output to the given output stream; swprintf() and vswprintf() write to
     the wide-character string ws.

     These functions write the output under the control of a format string
     that specifies how subsequent arguments (or arguments accessed via the
     variable-length argument facilities of stdarg(3)) are converted for
     output.

     The swprintf() and vswprintf() functions will fail if n or more wide
     characters were requested to be written,

     The format string is composed of zero or more directives: ordinary
     characters (not %), which are copied unchanged to the output stream; and
     conversion specifications, each of which results in fetching zero or more
     subsequent arguments.  Each conversion specification is introduced by the
     % character.  The arguments must correspond properly (after type
     promotion) with the conversion specifier.  After the %, the following
     appear in sequence:

     +o   An optional field, consisting of a decimal digit string followed by a
         $, specifying the next argument to access.  If this field is not
         provided, the argument following the last argument accessed will be
         used.  Arguments are numbered starting at 1.  If unaccessed arguments
         in the format string are interspersed with ones that are accessed the
         results will be indeterminate.

     +o   Zero or more of the following flags:

         '#'          The value should be converted to an ``alternate form''.
                      For c, d, i, n, p, s, and u conversions, this option has
                      no effect.  For o conversions, the precision of the
                      number is increased to force the first character of the
                      output string to a zero (except if a zero value is
                      printed with an explicit precision of zero).  For x and
                      X conversions, a non-zero result has the string '0x' (or
                      '0X' for X conversions) prepended to it.  For a, A, e,
                      E, f, F, g, and G conversions, the result will always
                      contain a decimal point, even if no digits follow it
                      (normally, a decimal point appears in the results of
                      those conversions only if a digit follows).  For g and G
                      conversions, trailing zeros are not removed from the
                      result as they would otherwise be.

         '0' (zero)   Zero padding.  For all conversions except n, the
                      converted value is padded on the left with zeros rather
                      than blanks.  If a precision is given with a numeric
                      conversion (d, i, o, u, i, x, and X), the 0 flag is
                      ignored.

         '-'          A negative field width flag; the converted value is to
                      be left adjusted on the field boundary.  Except for n
                      conversions, the converted value is padded on the right
                      with blanks, rather than on the left with blanks or
                      zeros.  A - overrides a 0 if both are given.

         ' ' (space)  A blank should be left before a positive number produced
                      by a signed conversion (a, A, d, e, E, f, F, g, G, or
                      i).

         '+'          A sign must always be placed before a number produced by
                      a signed conversion.  A + overrides a space if both are
                      used.

         '''          Decimal conversions (d, u, or i) or the integral portion
                      of a floating point conversion (f or F) should be
                      grouped and separated by thousands using the non-
                      monetary separator returned by localeconv(3).

     +o   An optional decimal digit string specifying a minimum field width.
         If the converted value has fewer characters than the field width, it
         will be padded with spaces on the left (or right, if the left-
         adjustment flag has been given) to fill out the field width.

     +o   An optional precision, in the form of a period . followed by an
         optional digit string.  If the digit string is omitted, the precision
         is taken as zero.  This gives the minimum number of digits to appear
         for d, i, o, u, x, and X conversions, the number of digits to appear
         after the decimal-point for a, A, e, E, f, and F conversions, the
         maximum number of significant digits for g and G conversions, or the
         maximum number of characters to be printed from a string for s
         conversions.

     +o   An optional length modifier, that specifies the size of the argument.
         The following length modifiers are valid for the d, i, n, o, u, x, or
         X conversion:

         Modifier          d, i           o, u, x, X            n
         hh                signed char    unsigned char         signed char *
         h                 short          unsigned short        short *
         l (ell)           long           unsigned long         long *
         ll (ell ell)      long long      unsigned long long    long long *
         j                 intmax_t       uintmax_t             intmax_t *
         t                 ptrdiff_t      (see note)            ptrdiff_t *
         z                 (see note)     size_t                (see note)
         q (deprecated)    quad_t         u_quad_t              quad_t *

         Note: the t modifier, when applied to a o, u, x, or X conversion,
         indicates that the argument is of an unsigned type equivalent in size
         to a ptrdiff_t.  The z modifier, when applied to a d or i conversion,
         indicates that the argument is of a signed type equivalent in size to
         a size_t.  Similarly, when applied to an n conversion, it indicates
         that the argument is a pointer to a signed type equivalent in size to
         a size_t.

         The following length modifier is valid for the a, A, e, E, f, F, g,
         or G conversion:

         Modifier    a, A, e, E, f, F, g, G
         L           long double

         The following length modifier is valid for the c or s conversion:

         Modifier    c         s
         l (ell)     wint_t    wchar_t *

     +o   A character that specifies the type of conversion to be applied.

     A field width or precision, or both, may be indicated by an asterisk '*'
     or an asterisk followed by one or more decimal digits and a '$' instead
     of a digit string.  In this case, an int argument supplies the field
     width or precision.  A negative field width is treated as a left
     adjustment flag followed by a positive field width; a negative precision
     is treated as though it were missing.  If a single format directive mixes
     positional (nn$) and non-positional arguments, the results are undefined.

     The conversion specifiers and their meanings are:

     diouxX  The int (or appropriate variant) argument is converted to signed
             decimal (d and i), unsigned octal (o), unsigned decimal (u), or
             unsigned hexadecimal (x and X) notation.  The letters ``abcdef''
             are used for x conversions; the letters ``ABCDEF'' are used for X
             conversions.  The precision, if any, gives the minimum number of
             digits that must appear; if the converted value requires fewer
             digits, it is padded on the left with zeros.

     DOU     The long int argument is converted to signed decimal, unsigned
             octal, or unsigned decimal, as if the format had been ld, lo, or
             lu respectively.  These conversion characters are deprecated, and
             will eventually disappear.

     eE      The double argument is rounded and converted in the style
             [-]d.ddde+-dd where there is one digit before the decimal-point
             character and the number of digits after it is equal to the
             precision; if the precision is missing, it is taken as 6; if the
             precision is zero, no decimal-point character appears.  An E
             conversion uses the letter 'E' (rather than 'e') to introduce the
             exponent.  The exponent always contains at least two digits; if
             the value is zero, the exponent is 00.

             For a, A, e, E, f, F, g, and G conversions, positive and negative
             infinity are represented as inf and -inf respectively when using
             the lowercase conversion character, and INF and -INF respectively
             when using the uppercase conversion character.  Similarly, NaN is
             represented as nan when using the lowercase conversion, and NAN
             when using the uppercase conversion.

     fF      The double argument is rounded and converted to decimal notation
             in the style [-]ddd.ddd, where the number of digits after the
             decimal-point character is equal to the precision specification.
             If the precision is missing, it is taken as 6; if the precision
             is explicitly zero, no decimal-point character appears.  If a
             decimal point appears, at least one digit appears before it.

     gG      The double argument is converted in style f or e (or F or E for G
             conversions).  The precision specifies the number of significant
             digits.  If the precision is missing, 6 digits are given; if the
             precision is zero, it is treated as 1.  Style e is used if the
             exponent from its conversion is less than -4 or greater than or
             equal to the precision.  Trailing zeros are removed from the
             fractional part of the result; a decimal point appears only if it
             is followed by at least one digit.

     aA      The double argument is converted to hexadecimal notation in the
             style [-]0xh.hhhp[+-]d, where the number of digits after the
             hexadecimal-point character is equal to the precision
             specification.  If the precision is missing, it is taken as
             enough to exactly represent the floating-point number; if the
             precision is explicitly zero, no hexadecimal-point character
             appears.  This is an exact conversion of the mantissa+exponent
             internal floating point representation; the [-]0xh.hhh portion
             represents exactly the mantissa; only denormalized mantissas have
             a zero value to the left of the hexadecimal point.  The p is a
             literal character 'p'; the exponent is preceded by a positive or
             negative sign and is represented in decimal, using only enough
             characters to represent the exponent.  The A conversion uses the
             prefix ``0X'' (rather than ``0x''), the letters ``ABCDEF''
             (rather than ``abcdef'') to represent the hex digits, and the
             letter 'P' (rather than 'p') to separate the mantissa and
             exponent.

     C       Treated as c with the l (ell) modifier.

     c       The int argument is converted to an unsigned char, then to a
             wchar_t as if by btowc(3), and the resulting character is
             written.

             If the l (ell) modifier is used, the wint_t argument is converted
             to a wchar_t and written.

     S       Treated as s with the l (ell) modifier.

     s       The char * argument is expected to be a pointer to an array of
             character type (pointer to a string) containing a multibyte
             sequence.  Characters from the array are converted to wide
             characters and written up to (but not including) a terminating
             NUL character; if a precision is specified, no more than the
             number specified are written.  If a precision is given, no null
             character need be present; if the precision is not specified, or
             is greater than the size of the array, the array must contain a
             terminating NUL character.

             If the l (ell) modifier is used, the wchar_t * argument is
             expected to be a pointer to an array of wide characters (pointer
             to a wide string).  Each wide character in the string is written.
             Wide characters from the array are written up to (but not
             including) a terminating wide NUL character; if a precision is
             specified, no more than the number specified are written
             (including shift sequences).  If a precision is given, no null
             character need be present; if the precision is not specified, or
             is greater than the number of characters in the string, the array
             must contain a terminating wide NUL character.

     p       The void * pointer argument is printed in hexadecimal (as if by
             '%#x' or '%#lx').

     n       The number of characters written so far is stored into the
             integer indicated by the int * (or variant) pointer argument.  No
             argument is converted.

     %       A '%' is written.  No argument is converted.  The complete
             conversion specification is '%%'.

     The decimal point character is defined in the program's locale (category
     LC_NUMERIC).

     In no case does a non-existent or small field width cause truncation of a
     numeric field; if the result of a conversion is wider than the field
     width, the field is expanded to contain the conversion result.

RETURN VALUES
     These functions return the number of characters printed (not including
     the trailing '\0' used to end output to strings).

SEE ALSO
     btowc(3), fputws(3), printf(3), putwc(3), setlocale(3), wcsrtombs(3),
     wscanf(3)

STANDARDS
     The wprintf(), fwprintf(), swprintf(), vwprintf(), vfwprintf() and
     vswprintf() functions conform to ISO/IEC 9899:1999 (``ISO C99'').

SECURITY CONSIDERATIONS
     Subject to the caveats noted in the printf(3).

BSD                             April 30, 2010                             BSD

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUES | SEE ALSO | STANDARDS | SECURITY CONSIDERATIONS