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wscanf, fwscanf, swscanf, vwscanf, vswscanf, vfwscanf - wide character

 

NAME

      wscanf, fwscanf, swscanf, vwscanf, vswscanf, vfwscanf - wide character
      input format conversion
 

LIBRARY

      Standard C Library (libc, -lc)
 

SYNOPSIS

      #include <stdio.h>
      #include <wchar.h>
 
      int
      wscanf(const wchar_t * restrict format, ...);
 
      int
      fwscanf(FILE * restrict stream, const wchar_t * restrict format, ...);
 
      int
      swscanf(const wchar_t * restrict str, const wchar_t * restrict format,
              ...);
 
      #include <stdarg.h>
 
      int
      vwscanf(const wchar_t * restrict format, va_list ap);
 
      int
      vswscanf(const wchar_t * restrict str, const wchar_t * restrict format,
              va_list ap);
 
      int
      vfwscanf(FILE * restrict stream, const wchar_t * restrict format,
              va_list ap);
 

DESCRIPTION

      The wscanf() family of functions scans input according to a format as
      described below.  This format may contain conversion specifiers; the
      results from such conversions, if any, are stored through the pointer
      arguments.  The wscanf() function reads input from the standard input
      stream stdin, fwscanf() reads input from the stream pointer stream, and
      swscanf() reads its input from the wide character string pointed to by
      str.  The vfwscanf() function is analogous to vfwprintf(3) and reads
      input from the stream pointer stream using a variable argument list of
      pointers (see stdarg(3)).  The vwscanf() function scans a variable argu‐
      ment list from the standard input and the vswscanf() function scans it
      from a wide character string; these are analogous to the vwprintf() and
      vswprintf() functions respectively.  Each successive pointer argument
      must correspond properly with each successive conversion specifier (but
      see the * conversion below).  All conversions are introduced by the %
      (percent sign) character.  The format string may also contain other char‐
      acters.  White space (such as blanks, tabs, or newlines) in the format
      string match any amount of white space, including none, in the input.
      Everything else matches only itself.  Scanning stops when an input char‐
      acter does not match such a format character.  Scanning also stops when
      an input conversion cannot be made (see below).
 

CONVERSIONS

      Following the % character introducing a conversion there may be a number
      of flag characters, as follows:
 
      *        Suppresses assignment.  The conversion that follows occurs as
               usual, but no pointer is used; the result of the conversion is
               simply discarded.
 
      hh       Indicates that the conversion will be one of dioux or n and the
               next pointer is a pointer to a char (rather than int).
 
      h        Indicates that the conversion will be one of dioux or n and the
               next pointer is a pointer to a short int (rather than int).
 
      l (ell)  Indicates that the conversion will be one of dioux or n and the
               next pointer is a pointer to a long int (rather than int), that
               the conversion will be one of a, e, f, or g and the next pointer
               is a pointer to double (rather than float), or that the conver‐
               sion will be one of c or s and the next pointer is a pointer to
               an array of wchar_t (rather than char).
 
      ll (ell ell)
               Indicates that the conversion will be one of dioux or n and the
               next pointer is a pointer to a long long int (rather than int).
 
      L        Indicates that the conversion will be one of a, e, f, or g and
               the next pointer is a pointer to long double.
 
      j        Indicates that the conversion will be one of dioux or n and the
               next pointer is a pointer to a intmax_t (rather than int).
 
      t        Indicates that the conversion will be one of dioux or n and the
               next pointer is a pointer to a ptrdiff_t (rather than int).
 
      z        Indicates that the conversion will be one of dioux or n and the
               next pointer is a pointer to a size_t (rather than int).
 
      q        (deprecated.)  Indicates that the conversion will be one of
               dioux or n and the next pointer is a pointer to a long long int
               (rather than int).
 
      In addition to these flags, there may be an optional maximum field width,
      expressed as a decimal integer, between the % and the conversion.  If no
      width is given, a default of “infinity” is used (with one exception,
      below); otherwise at most this many characters are scanned in processing
      the conversion.  Before conversion begins, most conversions skip white
      space; this white space is not counted against the field width.
 
      The following conversions are available:
 
      %     Matches a literal ‘%’.  That is, “%%” in the format string matches
            a single input ‘%’ character.  No conversion is done, and assign‐
            ment does not occur.
 
      d     Matches an optionally signed decimal integer; the next pointer must
            be a pointer to int.
 
      i     Matches an optionally signed integer; the next pointer must be a
            pointer to int.  The integer is read in base 16 if it begins with
            ‘0x’ or ‘0X’, in base 8 if it begins with ‘0’, and in base 10 oth‐
            erwise.  Only characters that correspond to the base are used.
 
      o     Matches an octal integer; the next pointer must be a pointer to
            unsigned int.
 
      u     Matches an optionally signed decimal integer; the next pointer must
            be a pointer to unsigned int.
 
      x, X  Matches an optionally signed hexadecimal integer; the next pointer
            must be a pointer to unsigned int.
 
      a, A, e, E, f, F, g, G
            Matches a floating-point number in the style of wcstod(3).  The
            next pointer must be a pointer to float (unless l or L is speci‐
            fied.)
 
      s     Matches a sequence of non-white-space wide characters; the next
            pointer must be a pointer to char, and the array must be large
            enough to accept the multibyte representation of all the sequence
            and the terminating NUL character.  The input string stops at white
            space or at the maximum field width, whichever occurs first.
 
            If an l qualifier is present, the next pointer must be a pointer to
            wchar_t, into which the input will be placed.
 
      S     The same as ls.
 
      c     Matches a sequence of width count wide characters (default 1); the
            next pointer must be a pointer to char, and there must be enough
            room for the multibyte representation of all the characters (no
            terminating NUL is added).  The usual skip of leading white space
            is suppressed.  To skip white space first, use an explicit space in
            the format.
 
            If an l qualifier is present, the next pointer must be a pointer to
            wchar_t, into which the input will be placed.
 
      C     The same as lc.
 
      [     Matches a nonempty sequence of characters from the specified set of
            accepted characters; the next pointer must be a pointer to char,
            and there must be enough room for the multibyte representation of
            all the characters in the string, plus a terminating NUL character.
            The usual skip of leading white space is suppressed.  The string is
            to be made up of characters in (or not in) a particular set; the
            set is defined by the characters between the open bracket [ charac‐
            ter and a close bracket ] character.  The set excludes those char‐
            acters if the first character after the open bracket is a circum‐
            flex ^.  To include a close bracket in the set, make it the first
            character after the open bracket or the circumflex; any other posi‐
            tion will end the set.  To include a hyphen in the set, make it the
            last character before the final close bracket; some implementations
            of wscanf() use “A-Z” to represent the range of characters between
            ‘A’ and ‘Z’.  The string ends with the appearance of a character
            not in the (or, with a circumflex, in) set or when the field width
            runs out.
 
            If an l qualifier is present, the next pointer must be a pointer to
            wchar_t, into which the input will be placed.
 
      p     Matches a pointer value (as printed by ‘%p’ in wprintf(3)); the
            next pointer must be a pointer to void.
 
      n     Nothing is expected; instead, the number of characters consumed
            thus far from the input is stored through the next pointer, which
            must be a pointer to int.  This is not a conversion, although it
            can be suppressed with the * flag.
 
      The decimal point character is defined in the program’s locale (category
      LC_NUMERIC).
 
      For backwards compatibility, a “conversion” of ‘%\0’ causes an immediate
      return of EOF.
      These functions return the number of input items assigned, which can be
      fewer than provided for, or even zero, in the event of a matching fail‐
      ure.  Zero indicates that, while there was input available, no conver‐
      sions were assigned; typically this is due to an invalid input character,
      such as an alphabetic character for a ‘%d’ conversion.  The value EOF is
      returned if an input failure occurs before any conversion such as an end-
      of-file occurs.  If an error or end-of-file occurs after conversion has
      begun, the number of conversions which were successfully completed is
      returned.
      fgetwc(3), scanf(3), wcrtomb(3), wcstod(3), wcstol(3), wcstoul(3),
      wprintf(3)
 

STANDARDS

      The fwscanf(), wscanf(), swscanf(), vfwscanf(), vwscanf() and vswscanf()
      functions conform to ISO/IEC 9899:1999 (“ISO C99”).
 

BUGS

      In addition to the bugs documented in scanf(3), wscanf() does not support
      the “A-Z” notation for specifying character ranges with the character
      class conversion (‘%[’).
 

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.