4746f25ac6
[skip ci] Reviewed-by: Matt Caswell <matt@openssl.org> (Merged from https://github.com/openssl/openssl/pull/7829)
79 lines
2.2 KiB
Text
79 lines
2.2 KiB
Text
=pod
|
|
|
|
=head1 NAME
|
|
|
|
BN_CTX_new, BN_CTX_secure_new, BN_CTX_free - allocate and free BN_CTX structures
|
|
|
|
=head1 SYNOPSIS
|
|
|
|
#include <openssl/bn.h>
|
|
|
|
BN_CTX *BN_CTX_new(void);
|
|
|
|
BN_CTX *BN_CTX_secure_new(void);
|
|
|
|
void BN_CTX_free(BN_CTX *c);
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
A B<BN_CTX> is a structure that holds B<BIGNUM> temporary variables used by
|
|
library functions. Since dynamic memory allocation to create B<BIGNUM>s
|
|
is rather expensive when used in conjunction with repeated subroutine
|
|
calls, the B<BN_CTX> structure is used.
|
|
|
|
BN_CTX_new() allocates and initializes a B<BN_CTX> structure.
|
|
BN_CTX_secure_new() allocates and initializes a B<BN_CTX> structure
|
|
but uses the secure heap (see L<CRYPTO_secure_malloc(3)>) to hold the
|
|
B<BIGNUM>s.
|
|
|
|
BN_CTX_free() frees the components of the B<BN_CTX> and the structure itself.
|
|
Since BN_CTX_start() is required in order to obtain B<BIGNUM>s from the
|
|
B<BN_CTX>, in most cases BN_CTX_end() must be called before the B<BN_CTX> may
|
|
be freed by BN_CTX_free(). If B<c> is NULL, nothing is done.
|
|
|
|
A given B<BN_CTX> must only be used by a single thread of execution. No
|
|
locking is performed, and the internal pool allocator will not properly handle
|
|
multiple threads of execution.
|
|
|
|
=head1 RETURN VALUES
|
|
|
|
BN_CTX_new() and BN_CTX_secure_new() return a pointer to the B<BN_CTX>.
|
|
If the allocation fails,
|
|
they return B<NULL> and sets an error code that can be obtained by
|
|
L<ERR_get_error(3)>.
|
|
|
|
BN_CTX_free() has no return values.
|
|
|
|
=head1 REMOVED FUNCTIONALITY
|
|
|
|
void BN_CTX_init(BN_CTX *c);
|
|
|
|
BN_CTX_init() is no longer available as of OpenSSL 1.1.0. Applications should
|
|
replace use of BN_CTX_init with BN_CTX_new instead:
|
|
|
|
BN_CTX *ctx;
|
|
ctx = BN_CTX_new();
|
|
if (!ctx)
|
|
/* error */
|
|
...
|
|
BN_CTX_free(ctx);
|
|
|
|
=head1 SEE ALSO
|
|
|
|
L<ERR_get_error(3)>, L<BN_add(3)>,
|
|
L<BN_CTX_start(3)>
|
|
|
|
=head1 HISTORY
|
|
|
|
BN_CTX_init() was removed in OpenSSL 1.1.0.
|
|
|
|
=head1 COPYRIGHT
|
|
|
|
Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved.
|
|
|
|
Licensed under the Apache License 2.0 (the "License"). You may not use
|
|
this file except in compliance with the License. You can obtain a copy
|
|
in the file LICENSE in the source distribution or at
|
|
L<https://www.openssl.org/source/license.html>.
|
|
|
|
=cut
|