| .TH CTYPE 3 |
| .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 (3). |
| .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 /usr/local/plan9/src/libc/port/ctype.c |
| .TP |
| .B /sys/include/ctype.h |
| for the macros. |
| .TP |
| .B /usr/local/plan9/src/libc/port/ctype.c |
| for the tables. |
| .SH "SEE ALSO |
| .IR isalpharune (3) |
| .SH BUGS |
| These macros are |
| .SM ASCII \c |
| -centric. |
