Subversion Repositories planix.SVN

.TH CTYPE 2

.SH NAME

isalpha, isupper, islower, isdigit, isxdigit, isalnum, isspace, ispunct, isprint, isgraph, iscntrl, isascii, toascii, _toupper, _tolower, toupper, tolower \- ASCII character classification

.SH SYNOPSIS

.B #include <u.h>

.br

.B #include <libc.h>

.br

.B #include <ctype.h>

.PP

.if t .2C

.B isalpha(c)

.PP

.B isupper(c)

.PP

.B islower(c)

.PP

.B isdigit(c)

.PP

.B isxdigit(c)

.PP

.B isalnum(c)

.PP

.B isspace(c)

.PP

.B ispunct(c)

.PP

.B isprint(c)

.PP

.B isgraph(c)

.PP

.B iscntrl(c)

.PP

.B isascii(c)

.PP

.B _toupper(c)

.PP

.B _tolower(c)

.PP

.B toupper(c)

.PP

.B tolower(c)

.PP

.B toascii(c)

.if t .1C

.SH DESCRIPTION

These macros classify

.SM ASCII\c

-coded integer values

by table lookup.

Each is a predicate returning nonzero for true,

zero for false.

.I Isascii

is defined on all integer values; the rest

are defined only where

.I isascii

is true and on the single non-\c

.SM ASCII

value

.BR EOF ;

see

.IR fopen (2).

.TP "\w'isalnum  'u"

.I isalpha

.I c

is a letter, a\-z or A\-Z

.TP

.I isupper

.I c

is an upper case letter, A\-Z

.TP

.I islower

.I c

is a lower case letter, a\-z

.TP

.I isdigit

.I c

is a digit, 0\-9

.TP

.I isxdigit

.I c

is a hexadecimal digit, 0\-9 or a\-f or A\-F

.TP

.I isalnum

.I c

is an alphanumeric character, a\-z or A\-Z or 0\-9

.TP

.I isspace

.I c

is a space, horizontal tab, newline, vertical tab, formfeed, or carriage return

(0x20, 0x9, 0xA, 0xB, 0xC, 0xD)

.TP

.I ispunct

.I c

is a punctuation character

(one of

.L

!"#$%&'()*+,-./:;<=>?@[\e]^_`{|}~\fR)

.TP

.I isprint

.I c

is a printing character, 0x20 (space)

through 0x7E (tilde) 

.TP

.I isgraph

.I c

is a visible printing character, 0x21 (exclamation) through 0x7E

(tilde)

.TP

.I iscntrl

.I c

is a delete character, 0x7F,

or ordinary control character, 0x0 through 0x1F

.TP

.I isascii

.I c

is an

.SM ASCII

character, 0x0 through 0x7F

.PP

.I Toascii

is not a classification macro;

it converts its argument to

.SM ASCII

range by

.IR and ing

with 0x7F.

.PP

If

.I c

is an upper case letter,

.I tolower

returns the lower case version of the character;

otherwise it returns the original character.

.I Toupper

is similar, returning the upper case version of a character

or the original character.

.I Tolower

and

.I toupper

are functions;

.I _tolower

and

.I _toupper

are corresponding macros which should only be used when it

is known that the argument is upper case or lower case, respectively.

.SH SOURCE

.TF /sys/src/libc/port/ctype.c

.TP

.B /sys/include/ctype.h

for the macros.

.TP

.B /sys/src/libc/port/ctype.c

for the tables.

.SH "SEE ALSO

.IR isalpharune (2)

.SH BUGS

These macros are

.SM ASCII\c

-centric.