ISCNTRL(3)

NAME
3.4 `iscntrl'--control character predicate

SYNOPSIS
     #include <ctype.h>
     int iscntrl(int C);

DESCRIPTION
`iscntrl' is a macro which classifies ASCII integer values by table lookup. It is a predicate returning non-zero for control characters, and 0 for other characters. It is defined only when `isascii'(C) is true or C is EOF.
   You can use a compiled subroutine instead of the macro definition by undefining the macro using ``#undef iscntrl''.

RETURNS
`iscntrl' returns non-zero if C is a delete character or ordinary control character (`0x7F' or `0x00'-`0x1F').

PORTABILITY
`iscntrl' is ANSI C.
   No supporting OS subroutines are required.

SEE ALSO
iscntrl is part of the library. The full documentation for is maintained as a Texinfo manual. If info and are properly installed at your site, the command

    info

will give you access to the complete manual.