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).
COMPLIANCE
iscntrl
is ANSI C.
No supporting OS subroutines are required.
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