freebsd-skq/lib/libc/locale/iscntrl.3

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.\"     @(#)iscntrl.3	8.1 (Berkeley) 6/4/93
.\" $FreeBSD$
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.Dd October 6, 2002
.Dt ISCNTRL 3
.Os
.Sh NAME
.Nm iscntrl
.Nd control character test
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In ctype.h
.Ft int
.Fn iscntrl "int c"
.Sh DESCRIPTION
The
.Fn iscntrl
function tests for any control character.
For single C
.Va char Ns s
locales (see
.Xr multibyte 3 )
the value of the argument is
representable as an
.Li unsigned char
or the value of
.Dv EOF .
In the ASCII character set, this includes the following characters
(with their numeric values shown in octal):
.Pp
.Bl -column \&000_``0''__ \&000_``0''__ \&000_``0''__ \&000_``0''__ \&000_``0''__
.It "\&000\ NUL \t001\ SOH \t002\ STX \t003\ ETX \t004\ EOT"
.It "\&005\ ENQ \t006\ ACK \t007\ BEL \t010\ BS \t011\ HT"
.It "\&012\ NL \t013\ VT \t014\ NP \t015\ CR \t016\ SO"
.It "\&017\ SI \t020\ DLE \t021\ DC1 \t022\ DC2 \t023\ DC3"
.It "\&024\ DC4 \t025\ NAK \t026\ SYN \t027\ ETB \t030\ CAN"
.It "\&031\ EM \t032\ SUB \t033\ ESC \t034\ FS \t035\ GS"
.It "\&036\ RS \t037\ US \t177\ DEL"
.El
.Sh RETURN VALUES
The
.Fn iscntrl
function returns zero if the character tests false and
returns non-zero if the character tests true.
.Sh COMPATIBILITY
Although
.Fn iscntrl
accepts arguments outside of the range of the
.Vt "unsigned char"
type in locales with large character sets,
this is a
.Bx 4.4
extension and the
.Fn iwcntrl
function should be used instead for maximum portability.
.Sh SEE ALSO
.Xr ctype 3 ,
.Xr iswcntrl 3 ,
.Xr multibyte 3 ,
.Xr ascii 7
.Sh STANDARDS
The
.Fn iscntrl
function conforms to
.St -isoC .