NAME

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

SYNTAX

#include <ctype.h>

isalpha(c)

. . . 

DESCRIPTION

These macros classify character-coded integer values according to the rules of the coded character set (codeset) identified by the last successful call to setlocale category LC_CTYPE. All macros return non-zero for true and zero for false.

If setlocale category LC_CTYPE has not been called successfully, or if character classification information is not available for a supported language, then characters are classified according to the rules of the ASCII 7-bit coded character set, returning 0 for values above octal 0177.

The macro isascii provides a result for all integer values. The rest provide a result for EOF and values in the character range of the codeset identified by the last successful call to setlocale category LC_CTYPE.

isalpha c is a letter

isupper c is an uppercase letter

islower c is a lowercase letter

isdigit c is a digit

isxdigit c is a hexadecimal digit [0-9], [A-F], or [a-f]

isalnum c is an alphanumeric character

isspace c is a space, tab, carriage return, new line, or formfeed

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

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

isgraph c is a printing character, like isprint except false for space

iscntrl c is a delete character (0177) or ordinary control character (less than 040) except for space characters

isascii c is an ASCII character, code less than 0200

SEE ALSO

setlocale(3int), stdio(3s), ascii(7)

Subroutines