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

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

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

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

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

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

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 char-acter character
     acter string ws.

     Extended locale versions of these functions are documented in wprintf_l(3).  See xlocale(3) for more
     information.

     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 con-verted converted
     verted for output.

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

     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:

     •   An optional field, consisting of a decimal digit string followed by a $, specifying the next argu-ment argument
         ment 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.

     •   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 num-ber number
                      ber 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 conver-sions, conversions,
                      sions, 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 dec-imal decimal
                      imal 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 conver-sion conversion
                      sion (f or F) should be grouped and separated by thousands using the non-monetary sep-arator separator
                      arator returned by localeconv(3).

     •   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.

     •   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 decimalpoint
         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.

     •   An optional length modifier, that specifies the size of the argument.  The following length modi-fiers modifiers
         fiers 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 con-version, conversion,
         version, indicates that the argument is of a signed type equivalent in size to a size_t.  Simi-larly, Similarly,
         larly, 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 *

     •   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 pre-cision; precision;
             cision; if the precision is missing, it is taken as 6; if the precision is zero, no decimal-point decimalpoint
             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 decimalpoint
             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 conver-sion conversion
             sion 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 specifica-tion. specification.
             tion.  If the precision is missing, it is taken as enough to exactly represent the floating-point floatingpoint
             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 char-acters characters
             acters 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 char-acters characters
             acters 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 (includ-ing (including
             ing shift sequences).  If a precision is given, no null character need be present; if the pre-cision precision
             cision 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.

SECURITY CONSIDERATIONS
     Refer to printf(3).

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

STANDARDS
     Subject to the caveats noted in the BUGS section of printf(3), the wprintf(), fwprintf(), swprintf(),
     vwprintf(), vfwprintf(), and vswprintf() functions conform to ISO/IEC 9899:1999 (``ISO C99'').

BSD                              July 5, 2003                              BSD

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