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 July 17, 2005 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.Ft int 44.Fn isblank_l "int c" "locale_t loc" 45.Sh DESCRIPTION 46The 47.Fn isblank 48function tests for a space or tab character. 49For any locale, this includes the following standard characters: 50.Bl -column XXXX 51.It Do \et Dc Ta Dq " " 52.El 53.Pp 54In the "C" locale, a successful 55.Fn isblank 56test is limited to these characters only. 57The value of the argument must be representable as an 58.Vt "unsigned char" 59or the value of 60.Dv EOF . 61.Pp 62The 63.Fn isblank_l 64function takes an explicit locale argument, whereas the 65.Fn isblank 66function uses the current global or per-thread locale. 67.Sh RETURN VALUES 68The 69.Fn isblank 70function returns zero if the character tests false and 71returns non-zero if the character tests true. 72.Sh COMPATIBILITY 73The 74.Bx 4.4 75extension of accepting arguments outside of the range of the 76.Vt "unsigned char" 77type in locales with large character sets is considered obsolete 78and may not be supported in future releases. 79The 80.Fn iswblank 81function should be used instead. 82.Sh SEE ALSO 83.Xr ctype 3 , 84.Xr iswblank 3 , 85.Xr xlocale 3 , 86.Xr ascii 7 87.Sh STANDARDS 88The 89.Fn isblank 90function 91conforms to 92.St -isoC-99 . 93The 94.Fn isblank_l 95function conforms to 96.St -p1003.1-2008 . 97