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.Dd December 19, 2022 29.Dt ISBLANK 3 30.Os 31.Sh NAME 32.Nm isblank , 33.Nm isblank_l 34.Nd space or tab character test 35.Sh LIBRARY 36.Lb libc 37.Sh SYNOPSIS 38.In ctype.h 39.Ft int 40.Fn isblank "int c" 41.Ft int 42.Fn isblank_l "int c" "locale_t loc" 43.Sh DESCRIPTION 44The 45.Fn isblank 46and 47.Fn isblank_l 48functions test 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 56or 57.Fn isblank_l 58test is limited to these characters only. 59The value of the argument must be representable as an 60.Vt "unsigned char" 61or the value of 62.Dv EOF . 63.Pp 64The 65.Fn isblank_l 66function takes an explicit locale argument, whereas the 67.Fn isblank 68function uses the current global or per-thread locale. 69.Sh RETURN VALUES 70The 71.Fn isblank 72and 73.Fn isblank_l 74functions return zero if the character tests false and 75return non-zero if the character tests true. 76.Sh COMPATIBILITY 77The 78.Bx 4.4 79extension of accepting arguments outside of the range of the 80.Vt "unsigned char" 81type in locales with large character sets is considered obsolete 82and may not be supported in future releases. 83The 84.Fn iswblank 85or 86.Fn iswblank_l 87function should be used instead. 88.Sh SEE ALSO 89.Xr ctype 3 , 90.Xr ctype_l 3 , 91.Xr iswblank 3 , 92.Xr iswblank_l 3 , 93.Xr xlocale 3 , 94.Xr ascii 7 95.Sh STANDARDS 96The 97.Fn isblank 98function 99conforms to 100.St -isoC-99 . 101The 102.Fn isblank_l 103function conforms to 104.St -p1003.1-2008 . 105