bsd man page for isascii

CTYPE(3)						     Library Functions Manual							  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 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)

       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)

7th Edition							   May 12, 1986 							  CTYPE(3)