NAME

isalnum — test for an alphanumeric character

SYNOPSIS

#include <ctype.h>

int isalnum(int c);

DESCRIPTION

The isalnum() function tests whether c is a character of class alpha or digit in the program's current locale, see the XBD specification, Locale .

In all cases c is an int, the value of which must be representable as an unsigned char or must equal the value of the macro EOF. If the argument has any other value, the behaviour is undefined.

RETURN VALUE

The isalnum() function returns non-zero if c is an alphanumeric character; otherwise it returns 0.

ERRORS

No errors are defined.

EXAMPLES

None.

APPLICATION USAGE

To ensure application portability, especially across natural languages, only this function and those listed in the SEE ALSO section should be used for character classification.

FUTURE DIRECTIONS

None.

SEE ALSO

isalpha(3) , iscntrl(3) , isdigit(3) , isgraph(3) , islower(3) , isprint(3) , ispunct(3) , isspace(3) , isupper(3) , isxdigit(3) , setlocale(3) , <ctype.h> , <stdio.h> , the XBD specification, Locale .

DERIVATION

Derived from Issue 1 of the SVID.