ISWDIGIT(3) Linux Programmer's Manual ISWDIGIT(3)

iswdigit - test for decimal digit wide character

#include <wctype.h>
int iswdigit(wint_t wc);

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'.

The iswdigit() function returns nonzero if wc is a wide character belonging to the wide-character class "digit". Otherwise, it returns zero.

For an explanation of the terms used in this section, see attributes(7).
Interface Attribute Value
iswdigit () Thread safety MT-Safe locale

POSIX.1-2001, POSIX.1-2008, C99.

The behavior of iswdigit() depends on the LC_CTYPE category of the current locale.

isdigit(3), iswctype(3)
2015-08-08 GNU