CTYPE(3C)

NAME

isalpha, isupper, islower, isdigit, isxdigit, isalnum, isspace, ispunct, isprint, isgraph, iscntrl, isascii − classify characters

SYNOPSIS

#include <ctype.h>

int isalpha (c)
int c;

. . .

HP-UX COMPATIBILITY

Level: HP-UX/RUN ONLY

Origin: System V

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 (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.

DIAGNOSTICS

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

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