wcstof man page on Archlinux

Man page or keyword search:  
man Server   11224 pages
apropos Keyword Search (all sections)
Output format
Archlinux logo
[printable version]

WCSTOD(3P)		   POSIX Programmer's Manual		    WCSTOD(3P)

PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
       implementation of this interface may differ (consult the	 corresponding
       Linux  manual page for details of Linux behavior), or the interface may
       not be implemented on Linux.

NAME
       wcstod, wcstof, wcstold — convert a wide-character string to a  double-
       precision number

SYNOPSIS
       #include <wchar.h>

       double wcstod(const wchar_t *restrict nptr, wchar_t **restrict endptr);
       float wcstof(const wchar_t *restrict nptr, wchar_t **restrict endptr);
       long double wcstold(const wchar_t *restrict nptr,
	   wchar_t **restrict endptr);

DESCRIPTION
       The  functionality described on this reference page is aligned with the
       ISO C standard. Any conflict between the	 requirements  described  here
       and  the	 ISO C	standard is unintentional. This volume of POSIX.1‐2008
       defers to the ISO C standard.

       These functions shall convert the initial portion of the wide-character
       string pointed to by nptr to double, float, and long double representa‐
       tion, respectively. First, they shall decompose the input  wide-charac‐
       ter string into three parts:

	1. An  initial, possibly empty, sequence of white-space wide-character
	   codes (as specified by iswspace())

	2. A subject sequence interpreted as a floating-point constant or rep‐
	   resenting infinity or NaN

	3. A  final  wide-character  string  of one or more unrecognized wide-
	   character codes, including the terminating null wide-character code
	   of the input wide-character string

       Then  they shall attempt to convert the subject sequence to a floating-
       point number, and return the result.

       The expected form of the subject sequence is an	optional  '+'  or  '−'
       sign, then one of the following:

	*  A  non-empty	 sequence  of  decimal	digits optionally containing a
	   radix character; then an optional exponent part consisting  of  the
	   wide	 character  'e' or the wide character 'E', optionally followed
	   by a '+' or '−' wide character, and then followed by	 one  or  more
	   decimal digits

	*  A 0x or 0X, then a non-empty sequence of hexadecimal digits option‐
	   ally containing a radix character; then an optional binary exponent
	   part	 consisting  of	 the  wide character 'p' or the wide character
	   'P', optionally followed by a '+' or '−' wide character,  and  then
	   followed by one or more decimal digits

	*  One	of INF or INFINITY, or any other wide string equivalent except
	   for case

	*  One of NAN or NAN(n-wchar-sequenceopt), or any  other  wide	string
	   ignoring case in the NAN part, where:

	       n-wchar-sequence:
		   digit
		   nondigit
		   n-wchar-sequence digit
		   n-wchar-sequence nondigit

       The  subject  sequence is defined as the longest initial subsequence of
       the input wide string, starting with  the  first	 non-white-space  wide
       character,  that is of the expected form. The subject sequence contains
       no wide characters if the input wide string  is	not  of	 the  expected
       form.

       If the subject sequence has the expected form for a floating-point num‐
       ber, the sequence of wide characters starting with the first  digit  or
       the  radix character (whichever occurs first) shall be interpreted as a
       floating constant according to the rules of the C language, except that
       the  radix  character  shall  be used in place of a period, and that if
       neither an exponent part nor a radix character  appears	in  a  decimal
       floating-point  number, or if a binary exponent part does not appear in
       a hexadecimal floating-point number, an exponent part of the  appropri‐
       ate  type  with value zero shall be assumed to follow the last digit in
       the string. If the subject  sequence  begins  with  a  minus-sign,  the
       sequence shall be interpreted as negated. A wide-character sequence INF
       or INFINITY shall be interpreted as an infinity,	 if  representable  in
       the  return  type,  else	 as if it were a floating constant that is too
       large for the range of the return type. A wide-character	 sequence  NAN
       or  NAN(n-wchar-sequenceopt)  shall  be	interpreted as a quiet NaN, if
       supported in the return type, else as if it  were  a  subject  sequence
       part  that  does not have the expected form; the meaning of the n-wchar
       sequences is implementation-defined. A pointer to the final wide string
       shall  be  stored  in  the  object  pointed to by endptr, provided that
       endptr is not a null pointer.

       If the subject sequence has the hexadecimal form	 and  FLT_RADIX	 is  a
       power  of  2,  the  conversion  shall  be rounded in an implementation-
       defined manner.

       The radix character shall be as defined in the current locale (category
       LC_NUMERIC).  In the POSIX locale, or in a locale where the radix char‐
       acter is not defined, the radix character shall default to  a  <period>
       ('.').

       In other than the C or POSIX locales, other implementation-defined sub‐
       ject sequences may be accepted.

       If the subject sequence is empty or does not have the expected form, no
       conversion shall be performed; the value of nptr shall be stored in the
       object pointed to by  endptr,  provided	that  endptr  is  not  a  null
       pointer.

       These functions shall not change the setting of errno if successful.

       Since  0 is returned on error and is also a valid return on success, an
       application wishing to check for error situations should set  errno  to
       0, then call wcstod(), wcstof(), or wcstold(), then check errno.

RETURN VALUE
       Upon  successful completion, these functions shall return the converted
       value. If no conversion could be performed, 0  shall  be	 returned  and
       errno may be set to [EINVAL].

       If  the	correct	 value	is  outside the range of representable values,
       ±HUGE_VAL, ±HUGE_VALF, or ±HUGE_VALL shall be  returned	(according  to
       the sign of the value), and errno shall be set to [ERANGE].

       If  the correct value would cause underflow, a value whose magnitude is
       no greater than the smallest normalized positive number in  the	return
       type shall be returned and errno set to [ERANGE].

ERRORS
       The wcstod() function shall fail if:

       ERANGE The value to be returned would cause overflow or underflow.

       The wcstod() function may fail if:

       EINVAL No conversion could be performed.

       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       If the subject sequence has the hexadecimal form and FLT_RADIX is not a
       power of 2, and the result is not  exactly  representable,  the	result
       should  be  one	of  the two numbers in the appropriate internal format
       that are adjacent to the hexadecimal floating source  value,  with  the
       extra  stipulation  that	 the  error should have a correct sign for the
       current rounding direction.

       If the subject sequence has the decimal form and	 at  most  DECIMAL_DIG
       (defined	 in  <float.h>)	 significant digits, the result should be cor‐
       rectly rounded. If the subject sequence D has the decimal form and more
       than  DECIMAL_DIG  significant digits, consider the two bounding, adja‐
       cent decimal strings L and U, both having DECIMAL_DIG significant  dig‐
       its, such that the values of L, D, and U satisfy "L<=D<=U".  The result
       should be one of the (equal or adjacent) values that would be  obtained
       by  correctly rounding L and U according to the current rounding direc‐
       tion, with the extra stipulation that  the  error  with	respect	 to  D
       should have a correct sign for the current rounding direction.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       fscanf(), iswspace(), localeconv(), setlocale(), wcstol()

       The  Base  Definitions  volume  of  POSIX.1‐2008,  Chapter  7,  Locale,
       <float.h>, <wchar.h>

COPYRIGHT
       Portions of this text are reprinted and reproduced in  electronic  form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
       -- Portable Operating System Interface (POSIX),	The  Open  Group  Base
       Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
       cal and Electronics Engineers,  Inc  and	 The  Open  Group.   (This  is
       POSIX.1-2008  with  the	2013  Technical Corrigendum 1 applied.) In the
       event of any discrepancy between this version and the original IEEE and
       The  Open Group Standard, the original IEEE and The Open Group Standard
       is the referee document. The original Standard can be  obtained	online
       at http://www.unix.org/online.html .

       Any  typographical  or  formatting  errors that appear in this page are
       most likely to have been introduced during the conversion of the source
       files  to  man page format. To report such errors, see https://www.ker‐
       nel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group		     2013			    WCSTOD(3P)
[top]

List of man pages available for Archlinux

Copyright (c) for man pages and the logo by the respective OS vendor.

For those who want to learn more, the polarhome community provides shell access and support.

[legal] [privacy] [GNU] [policy] [cookies] [netiquette] [sponsors] [FAQ]
Tweet
Polarhome, production since 1999.
Member of Polarhome portal.
Based on Fawad Halim's script.
....................................................................
Vote for polarhome
Free Shell Accounts :: the biggest list on the net