.\"	$OpenBSD: BIO_f_null.3,v 1.9 2018/05/01 17:05:05 schwarze Exp $
.\"	OpenSSL e117a890 Sep 14 12:14:41 2000 +0000
.\"
.\" This file was written by Dr. Stephen Henson <steve@openssl.org>.
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.Dd $Mdocdate: May 1 2018 $
.Dt BIO_F_NULL 3
.Os
.Sh NAME
.Nm BIO_f_null
.Nd null filter
.Sh SYNOPSIS
.In openssl/bio.h
.Ft const BIO_METHOD *
.Fo BIO_f_null
.Fa void
.Fc
.Sh DESCRIPTION
.Fn BIO_f_null
returns the null filter BIO method.
This is a filter BIO that does nothing.
As may be apparent, a null filter BIO is not particularly useful.
.Pp
All requests to a null filter BIO are passed through to the next BIO
in the chain: this means that a BIO chain containing a null filter BIO
behaves just as though the BIO was not there.
.Sh RETURN VALUES
.Fn BIO_f_null
returns the null filter BIO method.
.Sh SEE ALSO
.Xr BIO_new 3
.Sh HISTORY
.Fn BIO_f_null
first appeared in SSLeay 0.8.0 and has been available since
.Ox 2.4 .