.\"	$OpenBSD: isblank.3,v 1.7 2001/06/25 03:23:59 pjanzen Exp $
.\"
.\" Copyright (c) 1991 The Regents of the University of California.
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.\" 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 September 14, 1993
.Dt ISBLANK 3
.Os
.Sh NAME
.Nm isblank
.Nd blank-space character test
.Sh SYNOPSIS
.Fd #include <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
macro 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 CAVEATS
The argument to
.Fn isblank
must be
.Dv EOF
or representable as an
.Li unsigned char ;
otherwise, the result is undefined.