CTYPE(3C-SVR3)      RISC/os Reference Manual       CTYPE(3C-SVR3)



NAME
     ctype: isalpha, isupper, islower, isdigit, isxdigit, isal-
          num, isspace, ispunct, isprint, isgraph, iscntrl,
          isascii, toupper, tolower, toascii - character classif-
          ication macros

SYNOPSIS
     #include <ctype.h>

     int isalpha (c)
     int c;

     . . .

DESCRIPTION
     These macros classify character-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 [0-9].

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

     isalnum   c is an alphanumeric (letter or digit).

     isspace   c is a space, tab, carriage return, newline, vert-
               ical tab, or form-feed.

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

     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 an ordinary con-
               trol character (less than 040).

     isascii   c is an ASCII character, code less than 0200.

     tolower   c is converted to lower case.  Return value is



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CTYPE(3C-SVR3)      RISC/os Reference Manual       CTYPE(3C-SVR3)



               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
     stdio(3S), ascii(5).

DIAGNOSTICS
     If the argument to any of these macros is not in the domain
     of the function, the result is undefined.










































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