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

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.\"     @(#)iscntrl.3	8.1 (Berkeley) 6/4/93
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.Dd July 17, 2005
.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"
.Ft int
.Fn iscntrl_l "int c" "locale_t loc"
.Sh DESCRIPTION
The
.Fn iscntrl
function tests for any control character.
The value of the argument must be representable as an
.Vt "unsigned char"
or the value of
.Dv EOF .
.Pp
In the ASCII character set, this includes the following characters
(with their numeric values shown in octal):
.Bl -column \&000_``0''__ \&000_``0''__ \&000_``0''__ \&000_``0''__ \&000_``0''__
.It "\&000\ NUL" Ta "001\ SOH" Ta "002\ STX" Ta "003\ ETX" Ta "004\ EOT"
.It "\&005\ ENQ" Ta "006\ ACK" Ta "007\ BEL" Ta "010\ BS" Ta "011\ HT"
.It "\&012\ NL" Ta "013\ VT" Ta "014\ NP" Ta "015\ CR" Ta "016\ SO"
.It "\&017\ SI" Ta "020\ DLE" Ta "021\ DC1" Ta "022\ DC2" Ta "023\ DC3"
.It "\&024\ DC4" Ta "025\ NAK" Ta "026\ SYN" Ta "027\ ETB" Ta "030\ CAN"
.It "\&031\ EM" Ta "032\ SUB" Ta "033\ ESC" Ta "034\ FS" Ta "035\ GS"
.It "\&036\ RS" Ta "037\ US" Ta "177\ DEL" Ta \& Ta \&
.El
.Pp
The
.Fn iscntrl_l
function takes an explicit locale argument, whereas the
.Fn iscntrl
function uses the current global or per-thread locale.
.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
The
.Bx 4.4
extension of accepting arguments outside of the range of the
.Vt "unsigned char"
type in locales with large character sets is considered obsolete
and may not be supported in future releases.
The
.Fn iswcntrl
function should be used instead.
.Sh SEE ALSO
.Xr ctype 3 ,
.Xr iswcntrl 3 ,
.Xr xlocale 3 ,
.Xr ascii 7
.Sh STANDARDS
The
.Fn iscntrl
function conforms to
.St -isoC .
The
.Fn iscntrl_l
function conforms to
.St -p1003.1-2008 .