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WSCANF(3)                BSD Library Functions Manual                WSCANF(3)

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

LIBRARY
     Standard C Library (libc, -lc)

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

     int
     fwscanf(FILE *restrict stream, const wchar_t *restrict format, ...);

     int
     swscanf(const wchar_t *restrict ws, const wchar_t *restrict format, ...);

     int
     wscanf(const wchar_t *restrict format, ...);

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

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

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

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

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 ws.

     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
     argument 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 * con-version conversion
     version below).  All conversions are introduced by the % (percent sign) character.

     The format string may also contain other characters.  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 character does not match such a format character.
     Scanning also stops when an input conversion cannot be made (see below).

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

CONVERSIONS
     Following the % character introducing a conversion, there may be a number of flag characters, as fol-lows: follows:
     lows:

     *        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 conversion 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 inte-ger, integer,
     ger, 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 `%' charac-ter. character.
           ter.  No conversion is done, and assignment 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
           otherwise.  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 specified.)

     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 max-imum maximum
           imum 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 [ character and a close
           bracket ] character.  The set excludes those characters if the first character after the open
           bracket is a circumflex ^.  To include a close bracket in the set, make it the first character
           after the open bracket or the circumflex; any other position will end the set.  To include a
           hyphen in the set, make it the last character before the final close bracket; some implementa-tions implementations
           tions 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.

RETURN VALUES
     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 failure.  Zero indicates that, while there was input available,
     no conversions were assigned; typically, this is due to an invalid input character, such as an alpha-betic alphabetic
     betic 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.

SEE ALSO
     fgetwc(3), scanf(3), wcrtomb(3), wcstod(3), wcstol(3), wcstoul(3), wprintf(3), wscanf_l(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 (`%[').

BSD                              July 5, 2003                              BSD

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