.\"	$OpenBSD: isblank.3,v 1.12 2015/06/23 15:31:02 bentley Exp $
.\"
.\" Copyright (c) 1991 The Regents of the University of California.
.\" All rights reserved.
.\"
.\" This code is derived from software contributed to Berkeley by
.\" the American National Standards Committee X3, on Information
.\" Processing Systems.
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.Dd $Mdocdate: June 23 2015 $
.Dt ISBLANK 3
.Os
.Sh NAME
.Nm isblank
.Nd blank-space character test
.Sh SYNOPSIS
.In ctype.h
.Ft int
.Fn isblank "int c"
.Sh DESCRIPTION
The
.Fn isblank
function tests for the standard blank-space characters.
The standard blank-space characters are the following:
.Pp
.Bl -tag -width xxxxx -offset indent -compact
.It Sq \0
Space character.
.It Li \et
Horizontal tab.
.El
.Pp
In the C locale,
.Fn isblank
returns true only for the standard blank-space characters.
.Sh RETURN VALUES
The
.Fn isblank
function returns zero if the character tests false or
non-zero if the character tests true.
.Sh SEE ALSO
.Xr isalnum 3 ,
.Xr isalpha 3 ,
.Xr isascii 3 ,
.Xr iscntrl 3 ,
.Xr isdigit 3 ,
.Xr isgraph 3 ,
.Xr islower 3 ,
.Xr isprint 3 ,
.Xr ispunct 3 ,
.Xr isspace 3 ,
.Xr isupper 3 ,
.Xr isxdigit 3 ,
.Xr stdio 3 ,
.Xr toascii 3 ,
.Xr tolower 3 ,
.Xr toupper 3 ,
.Xr ascii 7
.Sh STANDARDS
The
.Fn isblank
function conforms to
.St -isoC-99 .
.Sh CAVEATS
The argument to
.Fn isblank
must be
.Dv EOF
or representable as an
.Li unsigned char ;
otherwise, the result is undefined.