CTYPE(3)

NAME
isalpha, isupper, islower, isdigit, isalnum, isspace, ispunct, isprint, iscntrl, isascii - character classification

SYNOPSIS
#include <ctype.h>

isalpha(c)

. . .

DESCRIPTION
These macros classify ASCII-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(3)).

isalpha
    c is a letter

isupper
    c is an upper case letter

islower
    c is a lower case letter

isdigit
    c is a digit

isalnum
    c is an alphanumeric character

isspace
    c is a space, tab, carriage return, newline, 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)

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

isascii
    c is an ASCII character, code less than 0200

SEE ALSO
ascii(7)