.\" @(#)ctype.3 6.4 (Berkeley) 05/12/86 .\" .TH CTYPE 3 "" .AT 3 .SH NAME isalpha, isupper, islower, isdigit, isxdigit, isalnum, isspace, ispunct, isprint, isgraph, iscntrl, isascii, toupper, tolower, toascii \- character classification macros .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 and .I toascii are 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 (3S)). .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 hex digit .TP .I isalnum .I c is an alphanumeric character .TP .I isspace .I c is a space, tab, carriage return, newline, vertical tab, 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 isgraph .I c is a printing character, similar to .I isprint except false for space. .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 .TP .I tolower .I c is converted to lower case. Return value is undefined if not .I isupper(c). .TP .I toupper .I c is converted to upper case. Return value is undefined if not .I islower(c). .TP .I toascii .I c is converted to be a valid ascii character. .SH "SEE ALSO" ascii(7)