@c ----------------------------------------------------------------------
@node isalnum, ctype
@subheading Syntax

@example
#include <ctype.h>

int isalnum(int c);
@end example

@subheading Description

Tells if @var{c} is any letter or digit.

@subheading Return Value

Nonzero if @var{c} is a letter or digit, else zero.



@subheading Portability

@portability ansi, posix