iswalnum

int iswalnum( wint_t ch );

Checks if the given wide character is an alphanumeric character, i.e. either a number (0123456789), an uppercase letter (ABCDEFGHIJKLMNOPQRSTUVWXYZ), a lowercase letter (abcdefghijklmnopqrstuvwxyz) or any alphanumeric character specific to the current locale.

Parameters

Return value

Non-zero value if the wide character is an alphanumeric character, zero otherwise.

Notes

ISO 30112 specifies which Unicode characters are include in POSIX alnum category.

Example

#include <stdio.h>
#include <locale.h>
#include <wchar.h>
#include <wctype.h>
 
int main(void)
{
    wchar_t c = L'\u13ad'; // the Cherokee letter HA ('Ꭽ')
    printf("in the default locale, iswalnum(%#x) = %d\n", c, !!iswalnum(c));
    setlocale(LC_ALL, "en_US.utf8");
    printf("in Unicode locale, iswalnum(%#x) = %d\n", c, !!iswalnum(c));
}

in the default locale, iswalnum(0x13ad) = 0
in Unicode locale, iswalnum(0x13ad) = 1

References

• C23 standard (ISO/IEC 9899:2023):
• TBD The iswalnum function (p: TBD)
• C17 standard (ISO/IEC 9899:2018):
• 7.30.2.1.1 The iswalnum function (p: 327)
• C11 standard (ISO/IEC 9899:2011):
• 7.30.2.1.1 The iswalnum function (p: 448)
• C99 standard (ISO/IEC 9899:1999):
• 7.25.2.1.1 The iswalnum function (p: 394)

See also