123 lines
3.7 KiB
Groff
123 lines
3.7 KiB
Groff
.\" $OpenBSD: BN_CTX_new.3,v 1.10 2023/04/25 17:21:51 tb Exp $
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.\" OpenSSL aafbe1cc Jun 12 23:42:08 2013 +0100
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.\"
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.\" This file was written by Ulf Moeller <ulf@openssl.org>.
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.\" Copyright (c) 2000, 2013 The OpenSSL Project. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\"
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\"
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in
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.\" the documentation and/or other materials provided with the
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.\" distribution.
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.\"
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.\" 3. All advertising materials mentioning features or use of this
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.\" software must display the following acknowledgment:
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.\" "This product includes software developed by the OpenSSL Project
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.\" for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
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.\"
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.\" 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
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.\" endorse or promote products derived from this software without
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.\" prior written permission. For written permission, please contact
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.\" openssl-core@openssl.org.
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.\"
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.\" 5. Products derived from this software may not be called "OpenSSL"
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.\" nor may "OpenSSL" appear in their names without prior written
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.\" permission of the OpenSSL Project.
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.\"
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.\" 6. Redistributions of any form whatsoever must retain the following
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.\" acknowledgment:
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.\" "This product includes software developed by the OpenSSL Project
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.\" for use in the OpenSSL Toolkit (http://www.openssl.org/)"
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
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.\" EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
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.\" ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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.\" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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.\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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.\" OF THE POSSIBILITY OF SUCH DAMAGE.
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.\"
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.Dd $Mdocdate: April 25 2023 $
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.Dt BN_CTX_NEW 3
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.Os
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.Sh NAME
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.Nm BN_CTX_new ,
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.Nm BN_CTX_free
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.Nd allocate and free BN_CTX structures
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.Sh SYNOPSIS
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.In openssl/bn.h
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.Ft BN_CTX *
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.Fo BN_CTX_new
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.Fa void
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.Fc
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.Ft void
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.Fo BN_CTX_free
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.Fa "BN_CTX *c"
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.Fc
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.Sh DESCRIPTION
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A
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.Vt BN_CTX
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is a structure that holds
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.Vt BIGNUM
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temporary variables used by library functions.
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Since dynamic memory allocation to create
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.Vt BIGNUM Ns s
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is rather expensive when used in conjunction with repeated subroutine
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calls, the
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.Vt BN_CTX
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structure is used.
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.Pp
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.Fn BN_CTX_new
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allocates and initializes a
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.Vt BN_CTX
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structure.
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.Pp
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.Fn BN_CTX_free
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frees the components of the
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.Vt BN_CTX
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and, if it was created by
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.Fn BN_CTX_new ,
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also the structure itself.
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If
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.Xr BN_CTX_start 3
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has been used on the
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.Vt BN_CTX ,
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.Xr BN_CTX_end 3
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must be called before the
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.Vt BN_CTX
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may be freed by
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.Fn BN_CTX_free .
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If
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.Fa c
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is a
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.Dv NULL
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pointer, no action occurs.
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.Sh RETURN VALUES
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.Fn BN_CTX_new
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returns a pointer to the
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.Vt BN_CTX .
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If the allocation fails, it returns
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.Dv NULL
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and sets an error code that can be obtained by
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.Xr ERR_get_error 3 .
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.Sh SEE ALSO
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.Xr BN_add 3 ,
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.Xr BN_CTX_start 3 ,
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.Xr BN_new 3
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.Sh HISTORY
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.Fn BN_CTX_new
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and
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.Fn BN_CTX_free
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first appeared in SSLeay 0.5.1 and have been available since
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.Ox 2.4 .
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