AT&T UNIX™PC Unix System V Users Manual - tenox

CTYPE ( 3C ) 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;
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)).
is alpha
isupper
islower
is digit
isxdigit
isalnum
isspace
ispunct
is print
is graph
iscntrl
c is a letter.
c is an upper-case letter.
c is a lower-case letter.
c is a digit [0-9] .
c is a hexadecimal digit [0-9], [A-F] or [a-f] .
c is an alphanumeric (letter or digit).
c is a space, tab, carriage return, new-line, vertical
tab, or form-feed.
c is a punctuation character (neither control nor
alphanumeric).
c is a printing character, code 040 (space)
through 0176 (tilde).
c is a printing character, like isprint except false
for space.
c is a delete character (0177) or an ordinary control
character (less than 040).
c is an ASCII character, code less than 0200.
isascii
DIAGNOSTICS
If the argument to any of these macros is not in the domain of the
function, the result is undefined.
SEE ALSO
ascii(S).
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