NAME

isalpha, isupper, islower, isdigit, isxdigit, isalnum, isspace, ispunct, isprint, isgraph, iscntrl, isascii, toupper, tolower, toascii − classify or translate characters

SYNOPSIS

#include <ctype.h>

int isalpha (c)
int c;

. . . 

DESCRIPTION

These macros classify character-coded integer values by table lookup.  Each is a predicate returning nonzero for true, zero for false.  Isascii is defined on all integer values; the rest are defined only where isascii is true and on the single non-ASCII value EOF (−1 − see stdio(3S)).

isalpha c is a letter. 

isupper c is an upper-case letter. 

islower c is a lower-case letter. 

isdigit c is a digit [0-9]. 

isxdigit c is a hexadecimal digit [0-9], [A-F] or [a-f]. 

isalnum c is an alphanumeric (letter or digit). 

isspace c is a space, tab, carriage return, new-line, vertical tab, or form-feed. 

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

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

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

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

isascii c is an ASCII character, code less than 0200. 

These macros return the translation of c. 

toupper(c) translate lower case letter to upper case. 

tolower(c) translate upper case letter to lower case. 

toascii(c) strip the eighth bit (parity bit). 

DIAGNOSTICS

If the argument to any of these macros is not in the domain of the function, the result is undefined. 

SEE ALSO

ascii(5). 

Version 2.3  —  July 04, 1985