CTYPE(3)                             BSD                              CTYPE(3)



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 a nonzero value for true, and 0 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 uppercase letter.

     islower        c is a lowercase 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).

     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 lowercase.  Return value is undefined if
                    not isupper(c).

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

     toascii        c is converted to be a valid ASCII character.

SEE ALSO
     ascii(7)