1.\" $OpenBSD: isblank.3,v 1.13 2017/09/05 03:16:13 schwarze Exp $ 2.\" 3.\" Copyright (c) 1991 The Regents of the University of California. 4.\" Copyright (c) 2017 Ingo Schwarze <schwarze@openbsd.org> 5.\" All rights reserved. 6.\" 7.\" This code is derived from software contributed to Berkeley by 8.\" the American National Standards Committee X3, on Information 9.\" Processing Systems. 10.\" 11.\" Redistribution and use in source and binary forms, with or without 12.\" modification, are permitted provided that the following conditions 13.\" are met: 14.\" 1. Redistributions of source code must retain the above copyright 15.\" notice, this list of conditions and the following disclaimer. 16.\" 2. Redistributions in binary form must reproduce the above copyright 17.\" notice, this list of conditions and the following disclaimer in the 18.\" documentation and/or other materials provided with the distribution. 19.\" 3. Neither the name of the University nor the names of its contributors 20.\" may be used to endorse or promote products derived from this software 21.\" without specific prior written permission. 22.\" 23.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33.\" SUCH DAMAGE. 34.\" 35.Dd $Mdocdate: September 5 2017 $ 36.Dt ISBLANK 3 37.Os 38.Sh NAME 39.Nm isblank , 40.Nm isblank_l 41.Nd blank-space single-byte character test 42.Sh SYNOPSIS 43.In ctype.h 44.Ft int 45.Fn isblank "int c" 46.Ft int 47.Fn isblank_l "int c" "locale_t locale" 48.Sh DESCRIPTION 49The 50.Fn isblank 51and 52.Fn isblank_l 53functions test for blank-space characters. 54In the C locale, the complete list of blank-space characters is: 55.Pp 56.Bl -tag -width xxxxx -offset indent -compact 57.It Sq \0 58Space character. 59.It Li \et 60Horizontal tab. 61.El 62.Pp 63.Ox 64always uses the C locale for these functions, 65ignoring the global locale, the thread-specific locale, and the 66.Fa locale 67argument. 68.Sh RETURN VALUES 69These functions return zero if the character tests false or 70non-zero if the character tests true. 71.Sh ENVIRONMENT 72On systems supporting non-ASCII single-byte character encodings, 73these functions may return non-zero for additional characters, 74and the results of 75.Fn isblank 76may depend on the 77.Ev LC_CTYPE 78.Xr locale 1 . 79.Sh SEE ALSO 80.Xr isalnum 3 , 81.Xr isalpha 3 , 82.Xr isascii 3 , 83.Xr iscntrl 3 , 84.Xr isdigit 3 , 85.Xr isgraph 3 , 86.Xr islower 3 , 87.Xr isprint 3 , 88.Xr ispunct 3 , 89.Xr isspace 3 , 90.Xr isupper 3 , 91.Xr iswblank 3 , 92.Xr isxdigit 3 , 93.Xr stdio 3 , 94.Xr toascii 3 , 95.Xr tolower 3 , 96.Xr toupper 3 , 97.Xr ascii 7 98.Sh STANDARDS 99The 100.Fn isblank 101function conforms to 102.St -isoC-99 , 103and 104.Fn isblank_l 105to 106.St -p1003.1-2008 . 107.Sh HISTORY 108The 109.Fn isblank 110function has been available since 111.Bx 4.4 , 112and 113.Fn isblank_l 114since 115.Ox 6.2 . 116.Sh CAVEATS 117The argument 118.Fa c 119must be 120.Dv EOF 121or representable as an 122.Li unsigned char ; 123otherwise, the result is undefined. 124