April 17, 2008 ISALNUM 3

### NAME

isalnum - alphanumeric character test

### LIBRARY

Standard C Library (libc, -lc)

### SYNOPSIS

```int` isalnum(```int c`)

### DESCRIPTION

The isalnum(``) function tests for any character for which isalpha(3) or isdigit(3) is true.

### RETURN VALUES

The isalnum(``) function returns zero if the character tests false and returns non-zero if the character tests true.

### SEE ALSO

ctype(3), isalpha(3), isascii(3), isblank(3), iscntrl(3), isdigit(3), isgraph(3), islower(3), isprint(3), ispunct(3), isspace(3), isupper(3), isxdigit(3), stdio(3), toascii(3), tolower(3), toupper(3), ascii(7)

### STANDARDS

The isalnum(``) function conforms to ANSI X3.159-1989 (``ANSI C89'') .

### CAVEATS

The argument to isalnum(``) must be ```EOF` or representable as an otherwise, the behavior is undefined. See the CAVEATS section of ctype(3) for more details.