.TH CTYPE 3 .UC .SH NAME isalpha, isupper, islower, isdigit, isalnum, isspace, ispunct, isprint, iscntrl, isascii \- character classification .SH SYNOPSIS .B #include .PP .B isalpha(c) .PP .B . . . .SH DESCRIPTION These macros classify ASCII-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-ASCII value EOF (see .IR stdio (3)). .TP 15n .I isalpha .I c is a letter .TP .I isupper .I c is an upper case letter .TP .I islower .I c is a lower case letter .TP .I isdigit .I c is a digit .TP .I isxdigit .I c is a hexadecimal digit .TP .I isalnum .I c is an alphanumeric character .TP .I isspace .I c is a space, tab, carriage return, newline, or formfeed .TP .I ispunct .I c is a punctuation character (neither control nor alphanumeric) .TP .I isprint .I c is a printing character, code 040(8) (space) through 0176 (tilde) .TP .I iscntrl .I c is a delete character (0177) or ordinary control character (less than 040). .TP .I isascii .I c is an ASCII character, code less than 0200 .SH "SEE ALSO" ascii(7)