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.\" $OpenBSD: SSL_want.3,v 1.2 2016/12/04 12:20:54 schwarze Exp $
.\" OpenSSL 9b86974e Aug 17 15:21:33 2015 -0400
.\"
.\" This file was written by Lutz Jaenicke <jaenicke@openssl.org>.
.\" Copyright (c) 2001, 2005 The OpenSSL Project. All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\"
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\"
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in
.\" the documentation and/or other materials provided with the
.\" distribution.
.\"
.\" 3. All advertising materials mentioning features or use of this
.\" software must display the following acknowledgment:
.\" "This product includes software developed by the OpenSSL Project
.\" for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
.\"
.\" 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
.\" endorse or promote products derived from this software without
.\" prior written permission. For written permission, please contact
.\" openssl-core@openssl.org.
.\"
.\" 5. Products derived from this software may not be called "OpenSSL"
.\" nor may "OpenSSL" appear in their names without prior written
.\" permission of the OpenSSL Project.
.\"
.\" 6. Redistributions of any form whatsoever must retain the following
.\" acknowledgment:
.\" "This product includes software developed by the OpenSSL Project
.\" for use in the OpenSSL Toolkit (http://www.openssl.org/)"
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
.\" EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
.\" ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
.\" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
.\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
.\" OF THE POSSIBILITY OF SUCH DAMAGE.
.\"
.Dd $Mdocdate: December 4 2016 $
.Dt SSL_WANT 3
.Os
.Sh NAME
.Nm SSL_want ,
.Nm SSL_want_nothing ,
.Nm SSL_want_read ,
.Nm SSL_want_write ,
.Nm SSL_want_x509_lookup
.Nd obtain state information TLS/SSL I/O operation
.Sh SYNOPSIS
.In openssl/ssl.h
.Ft int
.Fn SSL_want "const SSL *ssl"
.Ft int
.Fn SSL_want_nothing "const SSL *ssl"
.Ft int
.Fn SSL_want_read "const SSL *ssl"
.Ft int
.Fn SSL_want_write "const SSL *ssl"
.Ft int
.Fn SSL_want_x509_lookup "const SSL *ssl"
.Sh DESCRIPTION
.Fn SSL_want
returns state information for the
.Vt SSL
object
.Fa ssl .
.Pp
The other
.Fn SSL_want_*
calls are shortcuts for the possible states returned by
.Fn SSL_want .
.Pp
.Fn SSL_want
examines the internal state information of the
.Vt SSL
object.
Its return values are similar to those of
.Xr SSL_get_error 3 .
Unlike
.Xr SSL_get_error 3 ,
which also evaluates the error queue,
the results are obtained by examining an internal state flag only.
The information must therefore only be used for normal operation under
non-blocking I/O.
Error conditions are not handled and must be treated using
.Xr SSL_get_error 3 .
.Pp
The result returned by
.Fn SSL_want
should always be consistent with the result of
.Xr SSL_get_error 3 .
.Sh RETURN VALUES
The following return values can currently occur for
.Fn SSL_want :
.Bl -tag -width Ds
.It Dv SSL_NOTHING
There is no data to be written or to be read.
.It Dv SSL_WRITING
There are data in the SSL buffer that must be written to the underlying
.Vt BIO
layer in order to complete the actual
.Fn SSL_*
operation.
A call to
.Xr SSL_get_error 3
should return
.Dv SSL_ERROR_WANT_WRITE .
.It Dv SSL_READING
More data must be read from the underlying
.Vt BIO
layer in order to
complete the actual
.Fn SSL_*
operation.
A call to
.Xr SSL_get_error 3
should return
.Dv SSL_ERROR_WANT_READ.
.It Dv SSL_X509_LOOKUP
The operation did not complete because an application callback set by
.Xr SSL_CTX_set_client_cert_cb 3
has asked to be called again.
A call to
.Xr SSL_get_error 3
should return
.Dv SSL_ERROR_WANT_X509_LOOKUP .
.El
.Pp
.Fn SSL_want_nothing ,
.Fn SSL_want_read ,
.Fn SSL_want_write ,
and
.Fn SSL_want_x509_lookup
return 1 when the corresponding condition is true or 0 otherwise.
.Sh SEE ALSO
.Xr err 3 ,
.Xr ssl 3 ,
.Xr SSL_get_error 3
|
