Index for Section 3

Alphabetical listing for I

Bottom of page

iswalnum(3)
NAME
  iswalnum, iswalpha, iswcntrl, iswdigit, iswgraph, iswlower, iswprint,
  iswpunct, iswspace, iswupper, iswxdigit - Classify a wide character

LIBRARY
  Standard C Library (libc)

SYNOPSIS
  #include <wctype.h>

  int iswalnum(
	  wint_t wc);

  int iswalpha(
	  wint_t wc);

  int iswcntrl(
	  wint_t wc);

  int iswdigit(
	  wint_t wc);

  int iswgraph(
	  wint_t wc);

  int iswlower(
	  wint_t wc);

  int iswprint(
	  wint_t wc);

  int iswpunct(
	  wint_t wc);

  int iswspace(
	  wint_t wc);

  int iswupper(
	  wint_t wc);

  int iswxdigit(
	  wint_t wc);

STANDARDS
  Interfaces documented on this reference page conform to industry standards
  as follows:

  iswalnum(), iswalpha(), iswcntrl(), iswdigit(), iswgraph(), iswlower(),
  iswprint(), iswpunct(), iswspace(), iswupper(), iswxdigit(): XSH5.0

  Refer to the standards(5) reference page for more information about
  industry standards and associated tags.



PARAMETERS
  wc  Specifies a wide character for testing.

DESCRIPTION
  These functions test a wide character wc for membership in a character
  class in the current locale.	Each function tests to see if a wide
  character is part of a different character class.

  If the wide character is part of the character class, these functions
  return a nonzero value for true; otherwise, they return a value of 0 (zero)
  for false.

  Each function is named by adding the prefix isw to the name of the
  character class that the function tests. For example, the iswalpha()
  function tests whether the wide character specified by the wc parameter
  belongs to the alpha class.

  The following list identifies each function and describes the conditions
  under which it returns a true value:

  iswalnum()
	  When wc is a character of class alpha or class digit in the
	  program's current locale.

  iswalpha()
	  When wc is a character of class alpha in the program's current
	  locale. Characters in classes lower and upper automatically belong
	  to class alpha.

  iswcntrl()
	  When wc is a character of class cntrl in the program's current
	  locale.

  iswdigit()
	  When wc is a character of class digit in the program's current
	  locale. The following characters are included in this class:


	       0 1 2 3 4 5 6 7 8 9

  iswgraph()
	  When wc is a character of class graph in the program's current
	  locale. Characters in classes alpha, digit, and punct are
	  automatically in class graph.	 Unlike iswprint(), iswgraph()
	  returns FALSE for the space character.

  iswlower()
	  When wc is a character of class lower in the program's current
	  locale. At a minimum, the 26 lowercase US-ASCII characters are
	  included in this class. These are:


	       a b c d e f g h i j k l m n o p q r s t u v w x y z

  iswprint()
	  When wc is a character of class print in the program's current
	  locale. All characters in the class graph and the space character
	  are automatically included in class print.

  iswpunct()
	  When wc is a character of class punct in the program's current
	  locale.

  iswspace()
	  When wc is a character of class space in the program's current
	  locale. At a minimum, the space, form-feed, newline, carriage-
	  return, tab, and vertical-tab characters are included in this
	  class.

  iswupper()
	  When wc is a character of class upper in the program's current
	  locale. At a minimum, the 26 uppercase US-ASCII characters are
	  included in this class. These are:


	       A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

  iswxdigit()
	  When wc is a character of class xdigit in the program's current
	  locale. The following characters are included in this class:


	       0 1 2 3 4 5 6 7 8 9 A B C D E F a b c d e f

  These functions determine the class of a wide character based on the
  LC_CTYPE locale category.

NOTES
  [Tru64 UNIX]	The iswdigit(), iswxdigit(), and iswalnum() functions do not
  recognize Thai digits. Many applications make assumptions about how a digit
  character can be converted to its numeric equivalent.	 Changing the
  functions to recognize Thai digits would break these applications. Refer to
  TACTIS(5) for more information about Thai digits.

RETURN VALUES
  If the wide character tested is part of the particular character class,
  these functions return a nonzero value; otherwise, they return a value of 0
  (zero).

RELATED INFORMATION
  Files: locale(4)

  Functions: ctype(3), iswctype(3), setlocale(3), tolower(3), towctrans(3),
  towlower(3), wctrans(3), wctype(3)

  Others: i18n_intro(5), l10n_intro(5), standards(5)

Index for Section 3

Alphabetical listing for I

Top of page