iswalnum, iswalpha, iswcntrl, iswdigit, iswgraphiswlower,
iswprint, iswpunct, iswspace, iswupper, iswxdigit - Classify
a wide character
#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 );
Standard C Library (libc)
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.
Specifies a wide character for testing.
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: When
wc is a character of class alpha or class digit in the
program's current locale. 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. When wc is a character of class cntrl in the program's
current locale. 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 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. 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
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. When wc is a character of
class punct in the program's current locale. 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. 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
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.
[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.
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).
If the input value (wc) is not in the range of wide characters
defined by the current locale, the result is undefined.
To check the range of input values, compile applications
with standard compile options such as
-DOPEN_SOURCE. If the application compiles with any of the
standard compile options, the interfaces documented in
this reference page resolve as functions, which perform
internal range checking. A default compilation (that is,
no standard compile options specified) results in resolution
of the interfaces as macros, which do not perform
internal range checking.
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)
iswalnum(3)
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