1.\" Copyright (c) 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" the American National Standards Committee X3, on Information 6.\" Processing Systems. 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)iscntrl.3 8.1 (Berkeley) 6/4/93 33.\" $FreeBSD: head/lib/libc/locale/iscntrl.3 233992 2012-04-07 09:05:30Z joel $ 34.\" 35.Dd December 25, 2013 36.Dt ISCNTRL 3 37.Os 38.Sh NAME 39.Nm iscntrl , 40.Nm iscntrl_l 41.Nd control character test 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.In ctype.h 46.Ft int 47.Fn iscntrl "int c" 48.Ft int 49.Fn iscntrl_l "int c" "locale_t locale" 50.Sh DESCRIPTION 51The 52.Fn iscntrl 53and 54.Fn iscntrl_l 55functions test for any control character. 56The value of the argument must be representable as an 57.Vt "unsigned char" 58or the value of 59.Dv EOF . 60.Pp 61In the ASCII character set, this includes the following characters 62(with their numeric values shown in octal): 63.Bl -column \&000_``0''__ \&000_``0''__ \&000_``0''__ \&000_``0''__ \&000_``0''__ 64.It "\&000\ NUL" Ta "001\ SOH" Ta "002\ STX" Ta "003\ ETX" Ta "004\ EOT" 65.It "\&005\ ENQ" Ta "006\ ACK" Ta "007\ BEL" Ta "010\ BS" Ta "011\ HT" 66.It "\&012\ NL" Ta "013\ VT" Ta "014\ NP" Ta "015\ CR" Ta "016\ SO" 67.It "\&017\ SI" Ta "020\ DLE" Ta "021\ DC1" Ta "022\ DC2" Ta "023\ DC3" 68.It "\&024\ DC4" Ta "025\ NAK" Ta "026\ SYN" Ta "027\ ETB" Ta "030\ CAN" 69.It "\&031\ EM" Ta "032\ SUB" Ta "033\ ESC" Ta "034\ FS" Ta "035\ GS" 70.It "\&036\ RS" Ta "037\ US" Ta "177\ DEL" Ta \& Ta \& 71.El 72.Pp 73The 74.Fn iscntrl_l 75function takes an explicit 76.Fa locale 77argument, whereas the 78.Fn iscntrl 79function uses the current global or per-thread locale. 80.Sh RETURN VALUES 81The 82.Fn iscntrl 83and 84.Fn iscntrl_l 85functions return zero if the character tests false and 86returns non-zero if the character tests true. 87.Sh COMPATIBILITY 88The 89.Bx 4.4 90extension of accepting arguments outside of the range of the 91.Vt "unsigned char" 92type in locales with large character sets is considered obsolete 93and may not be supported in future releases. 94The 95.Fn iswcntrl 96and 97.Fn iswcntrl_l 98functions should be used instead. 99.Sh SEE ALSO 100.Xr ctype 3 , 101.Xr ctype_l 3 , 102.Xr iswcntrl 3 , 103.Xr iswcntrl_l 3 , 104.Xr xlocale 3 , 105.Xr ascii 7 106.Sh STANDARDS 107The 108.Fn iscntrl 109function conforms to 110.St -isoC . 111The 112.Fn iscntrl_l 113function conforms to 114.St -p1003.1-2008 . 115