ctype(3)

NAME

ctype - character type predicates and manipulation rou
tines

SYNOPSIS

#include <ctype.h>
isalpha(c)
...
toascii(c)
tolower(c)
toupper(c)
char c;

DESCRIPTION

Routines beginning with is are predicates that classify
the type of a character. Routines beginning with to con
vert characters. Each predicate returns TRUE if the con
dition is satisfied, and FALSE otherwise. In the current
implementation, predicates are macros that use table
lookup for efficiency.

isalnum c is an alphanumeric character (i.e., a

letter or digit)

isalpha c is a lower- or upper-case letter

isascii c is an ASCII character, code less than

0200

iscntrl c has a value less than octal 040 or is a

DEL (octal value 0177).

isdigit c is a digit.

islower c is a lower case letter.

isprint c is a printable character with octal value

040 (blank) through 0176 (tilde).

isprshort c is a printable short.

ispunct c is a punctuation character (neither con

trol nor alphanumeric).

isspace c is a space, tab, carriage return, new

line, or formfeed.

isupper c is an upper case letter.

isxdigit c is a hexadecimal digit (i.e., is 0-9 or

a-f).

toascii Converts c to an ascii by turning off high

order bits.

tolower Converts argument c from upper to lower

case.

toupper Converts argument c from lower to upper

case.

CTYPE(3)