fwscanf(3C)															       fwscanf(3C)

NAME

       fwscanf(), wscanf(), swscanf() - convert formatted  wide-character input

SYNOPSIS

DESCRIPTION

       The function reads from the named input stream.

       The function reads from the standard input stream The reads from the wide-character string s.

       Each  function  reads  wide-characters,	interprets  them according to a format, and stores the results in its arguments.  Each expects, as
       arguments, a control wide-character string format described below, and a set of pointer arguments  indicating  where  the  converted  input
       should  be stored.  The result is undefined if there are insufficient arguments for the format.	If the format is exhausted while arguments
       remain, the excess arguments are evaluated but are otherwise ignored.

       Conversions can be applied to the nth argument after the format in the argument list, rather than to the next  unused  argument.   In  this
       case, the conversion wide-character (see below) is replaced by the sequence where n is a decimal integer in the range This feature provides
       for the definition of format wide-character strings that select arguments in an order appropriate to specific languages.  In  format  wide-
       character  strings  containing the form of conversion specifications, it is unspecified whether numbered arguments in the argument list can
       be referenced from the format wide-character string more than once.

       The format can contain either form of a conversion specification, that is, or but the two forms cannot normally be mixed  within  a  single
       format wide-character string.  The only exception to this is that or can be mixed with the form.

       The function in all its forms allows for detection of a language-dependent radix character in the input string, encoded as a wide-character
       value.  The radix character is defined in the program's locale (category In the POSIX locale, or in a locale where the radix  character	is
       not defined, the radix character defaults to a period

       The format is a wide-character string composed of zero or more directives.  Each directive is composed of one of the following:

	      o  One or more white-space wide-characters (space, tab, newline, vertical-tab or form-feed characters);
	      o  An ordinary wide-character (neither nor a white-space character); or
	      o  A conversion specification.

       Each conversion specification is introduced by a or the sequence after which the following appear in sequence:

	      o  An optional assignment-suppressing character

	      o  An optional non-zero decimal integer that specifies the maximum field width.

	      o  An optional size modifier or indicating the size of the receiving object.

		 The  conversion  wide-characters and must be precede by (ell) if the corresponding argument is a pointer to rather than a pointer
		 to a character type.

		 The conversion wide-characters and must be preceded by if the corresponding argument is a pointer to  short  int  rather  than  a
		 pointer  to int, or by if it is a pointer to signed char, or by if it is a pointer to intmax_t, or by (ell) if it is a pointer to
		 long int, or by (ell-ell) if it is a pointer to long long, or by if it is a pointer to ptrdiff_t, or by if it	is  a  pointer	to
		 ssize_t.

		 Similarly,  the  conversion  wide-characters and must be preceded by if the corresponding argument is a pointer to unsigned short
		 int rather than a pointer to unsigned int, or by if it is a pointer to unsigned char, or by if it is a pointer to  uintmax_t,	or
		 by  (ell)  if	it  is	a pointer to unsigned long int, or by (ell-ell) if it is a pointer to unsigned long long, or by if it is a
		 pointer to unsigned ptrdiff_t, or by if it is a pointer to size_t.

		 The conversion wide-characters and must be preceded by (ell) if the corresponding argument is a pointer to double rather  than  a
		 pointer to float, or by if it is a pointer to long double.  If an or appears with any other conversion wide-character, the behav-
		 ior is undefined.

	      o  For Itanium(R)-based systems if the optional decimal floating point feature is installed  and	enabled,  the  following  optional
		 character specifications are allowed:

		 An optional specifying that a following or conversion specifier applies to an argument with type pointer to

		 An optional specifying that a following or conversion specifier applies to an argument with type pointer to

		 An optional specifying that a following or conversion specifier applies to an argument with type pointer to

		 The  behavior	of  the  or  conversion specifiers for decimal floating point numbers is the same as for double except hexadecimal
		 floating-point input is not accepted.

	      o  A conversion wide-character that specifies the type of conversion to  be  applied.   The  valid  conversion  wide-characters  are
		 described below.

       The  functions  execute each directive of the format in turn.  If a directive fails, as detailed below, the function returns.  Failures are
       described as input failures (due to the unavailability of input bytes) or matching failures (due to inappropriate input).

       A directive composed of one or more white-space wide-characters is executed by reading input until no more valid input can be read,  or	up
       to the first wide-character which is not a white-space wide-character, which remains unread.

       A  directive  that  is an ordinary wide-character is executed as follows.  The next wide-character is read from the input and compared with
       the wide-character that comprises the directive; if the comparison shows that they are not equivalent, the directive fails, and the differ-
       ing and subsequent wide-characters remain unread.

       A directive that is a conversion specification defines a set of matching input sequences, as described below for each conversion wide-char-
       acter.  A conversion specification is executed in the following steps:

       Input white-space wide-characters (as specified by are skipped, unless the conversion specification includes a or n conversion character.

       An item is read from the input, unless the conversion specification includes an conversion wide-character.  An input item is defined as the
       longest sequence of input wide-characters, not exceeding any specified field width, which is an initial subsequence of a matching sequence.
       The first wide-character, if any, after the input item remains unread.  If the length of the input item is 0, the execution of the  conver-
       sion specification fails; this condition is a matching failure, unless end-of-file, an encoding error, or a read error prevented input from
       the stream, in which case it is an input failure.  Except in the case of a conversion wide-character, the input item (or, in the case of  a
       conversion  specification, the count of input wide-characters) is converted to a type appropriate to the conversion wide-character.  If the
       input item is not a matching sequence, the execution of the conversion specification fails; this condition is a matching  failure.   Unless
       assignment  suppression	was indicated by a the result of the conversion is placed in the object pointed to by the first argument following
       the format argument that has not already received a conversion result if the conversion specification is introduced by or in the nth  argu-
       ment if introduced by the wide-character sequence If this object does not have an appropriate type, or if the result of the conversion can-
       not be represented in the space provided, the behavior is undefined.

       The following conversion wide-characters are valid:

	      Matches an optionally signed decimal integer, whose format is the same
			as expected for the subject sequence of with the value 10 for the base argument.  In the absence of a size  modifier,  the
			corresponding argument must be a pointer to int.

	      Matches an optionally signed integer, whose format is the same as expected for
			the  subject sequence of with 0 for the base argument.	In the absence of a size modifier, the corresponding argument must
			be a pointer to int.

	      Matches an optionally signed octal integer, whose format is the same as
			expected for the subject sequence of with the value 8 for the base argument.  In the absence of a size modifier, the  cor-
			responding argument must be a pointer to unsigned int.

	      Matches an optionally signed decimal integer, whose format is
			the  same as expected for the subject sequence of with the value 10 for the base argument.  In the absence of a size modi-
			fier, the corresponding argument must be a pointer to unsigned int.

	      Matches an optionally signed hexadecimal integer, whose format is
			the same as expected for the subject sequence of with the value 16 for the base argument.  In the absence of a size  modi-
			fier, the corresponding argument must be a pointer to unsigned int.

	      Matches an optionally signed floating-point number,
			whose  format  is  the	same  as expected for the subject sequence of In the absence of a size modifier, the corresponding
			argument must be a pointer to float.

       If the family of functions generates character string representations for infinity and NaN (a 7858 symbolic  entity  encoded  in  floating-
       point format) to support the ANSI/IEEE Std 754:1985 standard, the family of functions will recognize them as input.

	      Matches a sequence of non white-space wide-characters.
			If  no	(ell) qualifier is present, characters from the input field are converted as if by repeated calls to the function,
			with the conversion state described by an object initialized to zero before the first wide-character  is  converted.   The
			corresponding argument must be a pointer to a character array large enough to accept the sequence and the terminating null
			character, which will be added automatically.

       Otherwise, the corresponding argument must be a pointer to an array of large enough to accept the sequence and the terminating  null  wide-
       character, which will be added automatically.

	      Matches a non-empty sequence of wide-characters from
			a  set	of expected wide-characters (the scanset).  If no (ell) qualifier is present, wide-characters from the input field
			are converted as if by repeated calls to the function, with the conversion state described by  an  object  initialized	to
			zero  before  the  first  wide-character  is converted.  The corresponding argument must be a pointer to a character array
			large enough to accept the sequence and the terminating null character, which will be added automatically.

       If an (ell) qualifier is present, the corresponding argument must be a pointer to an array of large enough to accept the sequence  and  the
       terminating null wide-character, which will be added automatically.

       The  conversion	specification  includes  all subsequent wide characters in the format string up to and including the matching right square
       bracket ( The wide-characters between the square brackets (the scanlist) comprise the scanset, unless the  wide-character  after  the  left
       square bracket is a circumflex ( in which case the scanset contains all wide-characters that do not appear in the scanlist between the cir-
       cumflex and the right square bracket.  If the conversion specification begins with or the right square bracket is included in the  scanlist
       and  the  next  right square bracket is the matching right square bracket that ends the conversion specification; otherwise the first right
       square bracket is the one that ends the conversion specification.  If a is in the scanlist and is not the  first  wide-character,  nor  the
       second where the first wide-character is a nor the last wide-character, the behavior is implementation-dependent.

	      Matches a sequence of wide-characters of the number specified by
			the field width (1 if no field width is present in the conversion specification).  If no (ell) qualifier is present, wide-
			characters from the input field are converted as if by repeated calls to the function, with the conversion state described
			by  an	object	initialized  to  zero  before the first wide-character is converted.  The corresponding argument must be a
			pointer to a character array large enough to accept the sequence.  No null character is added.	Otherwise, the correspond-
			ing argument must be a pointer to an array of large enough to accept the sequence.  No null wide-character is added.

	      Matches an implementation-dependent set of sequences, which must be
			the  same  as  the  set of sequences that is produced by the conversion of the corresponding functions.  The corresponding
			argument must be a pointer to a pointer to void.  If the input item is a value converted earlier during the  same  program
			execution,  the  pointer  that results will compare equal to that value; otherwise the behavior of the conversion is unde-
			fined.

	      No input is consumed.
			The corresponding argument must be a pointer to the integer into which is to be written the number of wide-characters read
			from  the  input  so  far  by  this call to the functions.  Execution of a conversion specification does not increment the
			assignment count returned at the completion of execution of the function.

	      Same as

	      S 	Same as

	      Matches a single
			no conversion or assignment occurs.  The complete conversion specification must be

       If a conversion specification is invalid, the behavior is undefined.

       The conversion characters and are also valid and behave the same as, respectively, and

       If end-of-file is encountered during input, conversion is terminated.  If end-of-file occurs before any wide-characters matching  the  cur-
       rent  conversion  specification (except for have been read (other than leading white-space, where permitted), execution of the current con-
       version specification terminates with an input failure.	Otherwise, unless execution of the current conversion specification is	terminated
       with a matching failure, execution of the following conversion specification (if any) is terminated with an input failure.

       Reaching the end of the string in is equivalent to encountering end-of-file for

       If conversion terminates on a conflicting input, the offending input is left unread in the input.  Any trailing white space (including new-
       line) is left unread unless matched by a conversion specification.  The success of literal  matches  and  suppressed  assignments  is  only
       directly determinable via the conversion specification.

       The  and functions may mark the field of the file associated with stream for update.  The field will be marked for update by the first suc-
       cessful execution of or using stream that returns data not supplied by a prior call to

APPLICATION USAGE

       After or is applied to a stream, the stream becomes wide-oriented (see orientation(5)).

       In format strings containing the form of conversion specifications, each argument in the argument list is used exactly once.

       The prototypes of these functions are available to applications if they are:

	      a. conformant.

	      b. Compiled with macro with a value >=500.

	      c. Compiled with macro with a value >= 200112.

RETURN VALUE

       Upon successful completion, these functions return the number of successfully matched and assigned input items; this number can be 0 in the
       event  of  an  early  matching  failure.   If the input ends before the first matching failure or conversion, is returned.  If a read error
       occurs the error indicator for the stream is set, is returned, and is set to indicate the error.

ERRORS

       For the conditions under which the functions will fail and may fail, refer to In addition, may fail if:

	      Input byte sequence does not form a valid character.

	      There are insufficient arguments.

	      Insufficient storage space is available.

       In addition, may fail if:

	      The stream pointed to by
			     stream is byte-oriented.

       In addition, may fail if:

	      is byte-oriented.

EXAMPLES

       The call:

       with the input line:

       will assign to n the value 3, to i the value 25, x the value 5.432, and name will contain the string

       The call:

       with input:

       will assign 56 to i, 789.0 to x, skip 0123, and place the string 56 in name.  The next call to will return the character

AUTHOR

       were developed by HP and Mitsubishi Electric Corporation.

SEE ALSO

       fwprintf(3C), getwc(3C), setlocale(3C), wcstod(3C), wcstol(3C), wcrtomb(3C), wcstoul(3C),  langinfo(5),	orientation(5),  thread_safety(5),
       glossary(9).

																       fwscanf(3C)