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.\" 3. 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.\" 30.Dd December 19, 2022 31.Dt ISBLANK 3 32.Os 33.Sh NAME 34.Nm isblank , 35.Nm isblank_l 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 48and 49.Fn isblank_l 50functions test for a space or tab character. 51For any locale, this includes the following standard characters: 52.Bl -column XXXX 53.It Do \et Dc Ta Dq " " 54.El 55.Pp 56In the "C" locale, a successful 57.Fn isblank 58or 59.Fn isblank_l 60test is limited to these characters only. 61The value of the argument must be representable as an 62.Vt "unsigned char" 63or the value of 64.Dv EOF . 65.Pp 66The 67.Fn isblank_l 68function takes an explicit locale argument, whereas the 69.Fn isblank 70function uses the current global or per-thread locale. 71.Sh RETURN VALUES 72The 73.Fn isblank 74and 75.Fn isblank_l 76functions return zero if the character tests false and 77return non-zero if the character tests true. 78.Sh COMPATIBILITY 79The 80.Bx 4.4 81extension of accepting arguments outside of the range of the 82.Vt "unsigned char" 83type in locales with large character sets is considered obsolete 84and may not be supported in future releases. 85The 86.Fn iswblank 87or 88.Fn iswblank_l 89function should be used instead. 90.Sh SEE ALSO 91.Xr ctype 3 , 92.Xr ctype_l 3 , 93.Xr iswblank 3 , 94.Xr iswblank_l 3 , 95.Xr xlocale 3 , 96.Xr ascii 7 97.Sh STANDARDS 98The 99.Fn isblank 100function 101conforms to 102.St -isoC-99 . 103The 104.Fn isblank_l 105function conforms to 106.St -p1003.1-2008 . 107