This documentation is copyright © 1998-2001 Sandro Sigala <sandro@sigala.it>.
All rights reserved.
Released under the GNU General Public License.
isalnum
Prototype
#include <ctype.h>
int isalnum(int c);
Description
Returns a true value for any character for which isalpha
or isdigit
is true.
Example
#include <ctype.h>
/*
* Return a true value if the argument string is a regular C
* identifier.
*/
int is_identifier(const char *s)
{
if (!isalpha(*s) && *s != '_')
return 0;
for (++s; *s != '\0'; ++s)
if (!isalnum(*s) && *s != '_')
return 0;
return 1;
}
References
ISO C 9899:1990 7.3.1.1