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wprintf, fwprintf, swprintf, vwprintf, vfwprintf, vswprintf - formatted

 

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 out‐
      put.
 
      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 char‐
      acters (not %), which are copied unchanged to the output stream; and con‐
      version 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 promo‐
      tion) 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 argument to access.  If this field is not pro‐
          vided, 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 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 con‐
                       verted 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-mone‐
                       tary separator 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-adjust‐
          ment 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 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 con‐
          versions.
 
            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 *
 
            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 ‘$’ instead
      of a digit string.  In this case, an int argument supplies the field
      width or precision.  A negative field width is treated as a left adjust‐
      ment flag followed by a positive field width; a negative precision is
      treated as though it were missing.  If a single format directive mixes
      positional (nn$) 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; if the precision is missing, it is taken as 6; if the
              precision is zero, no decimal-point character appears.  An E con‐
              version 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 hex‐
              adecimal-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 explic‐
              itly 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 writ‐
              ten.
 
              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 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 charac‐
              ter need be present; if the precision is not specified, or is
              greater than the size of the array, the array must contain a ter‐
              minating 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 includ‐
              ing) a terminating wide NUL character; if a precision is speci‐
              fied, 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 con‐
              tain 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 inte‐
              ger indicated by the int * (or variant) pointer argument.  No
              argument is converted.
 
      %       A ‘%’ is written.  No argument is converted.  The complete con‐
              version 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.
      Refer to printf(3).
      btowc(3), fputws(3), printf(3), putwc(3), setlocale(3), wcsrtombs(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”).
 

Sections

Based on BSD UNIX
FreeBSD is an advanced operating system for x86 compatible (including Pentium and Athlon), amd64 compatible (including Opteron, Athlon64, and EM64T), UltraSPARC, IA-64, PC-98 and ARM architectures. It is derived from BSD, the version of UNIX developed at the University of California, Berkeley. It is developed and maintained by a large team of individuals. Additional platforms are in various stages of development.