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NAME
iswdigit - test for decimal digit wide character
LIBRARY
Standard C library (libc, -lc)
SYNOPSIS
#include <wctype.h>
int iswdigit(wint_t wc);
DESCRIPTION
The iswdigit() function is the wide-character equivalent of the isdigit(3) function. It tests whether wc
is a wide character belonging to the wide-character class "digit".
The wide-character class "digit" is a subclass of the wide-character class "xdigit", and therefore also a
subclass of the wide-character class "alnum", of the wide-character class "graph" and of the wide-
character class "print".
Being a subclass of the wide character class "print", the wide-character class "digit" is disjoint from
the wide-character class "cntrl".
Being a subclass of the wide-character class "graph", the wide-character class "digit" is disjoint from
the wide-character class "space" and its subclass "blank".
Being a subclass of the wide-character class "alnum", the wide-character class "digit" is disjoint from
the wide-character class "punct".
The wide-character class "digit" is disjoint from the wide-character class "alpha" and therefore also
disjoint from its subclasses "lower", "upper".
The wide-character class "digit" always contains exactly the digits '0' to '9'.
RETURN VALUE
The iswdigit() function returns nonzero if wc is a wide character belonging to the wide-character class
"digit". Otherwise, it returns zero.
ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7).
┌──────────────────────────────────────────────────────────────────────┬───────────────┬────────────────┐
│ Interface │ Attribute │ Value │
├──────────────────────────────────────────────────────────────────────┼───────────────┼────────────────┤
│ iswdigit() │ Thread safety │ MT-Safe locale │
└──────────────────────────────────────────────────────────────────────┴───────────────┴────────────────┘
STANDARDS
C11, POSIX.1-2008.
HISTORY
POSIX.1-2001, C99.
NOTES
The behavior of iswdigit() depends on the LC_CTYPE category of the current locale.
SEE ALSO
isdigit(3), iswctype(3)
Linux man-pages 6.15 2025-05-17 iswdigit(3)