NAME

isalpha, isupper, islower, isdigit, isxdigit, isalnum, isspace, ispunct, isprint, isgraph, iscntrl, isascii, toupper, tolower, toascii − character classification macros

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 and toascii are defined on all integer values; the rest are defined only where isascii is true and on the single non-ASCII value EOF (see stdio(3S)).

isalpha c is a letter

isupper c is an upper case letter

islower c is a lower case letter

isdigit c is a digit

isxdigit c is a hex digit

isalnum c is an alphanumeric character

isspace c is a space, tab, carriage return, newline, vertical tab, or formfeed

ispunct c is a punctuation character (neither control nor alphanumeric nor space)

isprint c is a printing character, code 040(8) (space) through 0176 (tilde)

isgraph c is a printing character, similar to isprint except false for space. 

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

isascii c is an ASCII character, code less than 0200

tolower c is converted to lower case.  Return value is undefined if not isupper(c). 

toupper c is converted to upper case.  Return value is undefined if not islower(c). 

toascii c is converted to be a valid ascii character. 

SEE ALSO

ascii(7)
 

PRPQs 5799-WZQ/5799-PFF: IBM/4.3  —  July 1987