@(#)ctype.3 6.4 (Berkeley) 05/12/86

.AT 3 isalpha, isupper, islower, isdigit, isxdigit, isalnum, isspace, ispunct, isprint, isgraph, iscntrl, isascii, toupper, tolower, toascii - character classification macros #include <ctype.h>

isalpha(c)

. . .

These macros classify ASCII-coded integer values by table lookup. Each is a predicate returning nonzero for true, zero for false. Isascii and toascii are defined on all integer values; the rest are defined only where isascii is true and on the single non-ASCII value EOF (see stdio (3S)).

15n isalpha c is a letter

isupper c is an upper case letter

islower c is a lower case letter

isdigit c is a digit

isxdigit c is a hex digit

isalnum c is an alphanumeric character

isspace c is a space, tab, carriage return, newline, vertical tab, or formfeed

ispunct c is a punctuation character (neither control nor alphanumeric)

isprint c is a printing character, code 040(8) (space) through 0176 (tilde)

isgraph c is a printing character, similar to isprint except false for space.

iscntrl c is a delete character (0177) or ordinary control character (less than 040).

isascii c is an ASCII character, code less than 0200

tolower c is converted to lower case. Return value is undefined if not isupper(c).

toupper c is converted to upper case. Return value is undefined if not islower(c).

toascii c is converted to be a valid ascii character.

ascii(7)