1.\" Copyright (c) 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 4. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)isblank.3 8.1 (Berkeley) 6/4/93 29.\" $FreeBSD$ 30.\" 31.Dd September 3, 2009 32.Dt ISBLANK 3 33.Os 34.Sh NAME 35.Nm isblank 36.Nd space or tab character test 37.Sh LIBRARY 38.Lb libc 39.Sh SYNOPSIS 40.In ctype.h 41.Ft int 42.Fn isblank "int c" 43.Sh DESCRIPTION 44The 45.Fn isblank 46function tests for a space or tab character. 47For any locale, this includes the following standard characters: 48.Pp 49.Bl -column \&`\et''___ \&``\et''___ 50.It "\&``\et''\t`` ''" 51.El 52.Pp 53In the "C" locale 54.Fn isblank 55successful test is limited to this characters only. 56The value of the argument must be representable as an 57.Vt "unsigned char" 58or the value of 59.Dv EOF . 60.Pp 61.Em NOTE : 62if the value passed to the 63.Fn isblank 64function is a 65.Vt signed char , 66as is usually the case, it must be cast to an 67.Vt unsigned char 68to avoid sign-extension errors. 69.Sh RETURN VALUES 70The 71.Fn isblank 72function returns zero if the character tests false and 73returns non-zero if the character tests true. 74.Sh COMPATIBILITY 75The 76.Bx 4.4 77extension of accepting arguments outside of the range of the 78.Vt "unsigned char" 79type in locales with large character sets is considered obsolete 80and may not be supported in future releases. 81The 82.Fn iswblank 83function should be used instead. 84.Sh SEE ALSO 85.Xr ctype 3 , 86.Xr iswblank 3 , 87.Xr ascii 7 88.Sh STANDARDS 89The 90.Fn isblank 91function 92conforms to 93.St -isoC-99 . 94