| =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 OpenSSL license (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 |
