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1=pod
2
3=head1 NAME
4
c952780c 5BN_CTX_new, BN_CTX_secure_new, BN_CTX_free - allocate and free BN_CTX structures
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6
7=head1 SYNOPSIS
8
9 #include <openssl/bn.h>
10
11 BN_CTX *BN_CTX_new(void);
12
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13 BN_CTX *BN_CTX_secure_new(void);
14
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15 void BN_CTX_free(BN_CTX *c);
16
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17=head1 DESCRIPTION
18
15701211
DSH
19A B<BN_CTX> is a structure that holds B<BIGNUM> temporary variables used by
20library functions. Since dynamic memory allocation to create B<BIGNUM>s
21is rather expensive when used in conjunction with repeated subroutine
22calls, the B<BN_CTX> structure is used.
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24BN_CTX_new() allocates and initializes a B<BN_CTX> structure.
25BN_CTX_secure_new() allocates and initializes a B<BN_CTX> structure
26but uses the secure heap (see L<CRYPTO_secure_malloc(3)>) to hold the
27B<BIGNUM>s.
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29BN_CTX_free() frees the components of the B<BN_CTX>, and if it was
30created by BN_CTX_new(), also the structure itself.
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31If L<BN_CTX_start(3)> has been used on the B<BN_CTX>,
32L<BN_CTX_end(3)> must be called before the B<BN_CTX>
37e48b88 33may be freed by BN_CTX_free().
23a1d5e9 34If B<c> is NULL, nothing is done.
37e48b88 35
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36=head1 RETURN VALUES
37
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38BN_CTX_new() and BN_CTX_secure_new() return a pointer to the B<BN_CTX>.
39If the allocation fails,
40they return B<NULL> and sets an error code that can be obtained by
9b86974e 41L<ERR_get_error(3)>.
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43BN_CTX_free() has no return values.
44
45=head1 REMOVED FUNCTIONALITY
46
47 void BN_CTX_init(BN_CTX *c);
48
49BN_CTX_init() is no longer available as of OpenSSL 1.1.0. Applications should
50replace use of BN_CTX_init with BN_CTX_new instead:
51
52 BN_CTX *ctx;
53 ctx = BN_CTX_new();
54 if(!ctx) /* Handle error */
55 ...
56 BN_CTX_free(ctx);
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57
58=head1 SEE ALSO
59
9e183d22 60L<ERR_get_error(3)>, L<BN_add(3)>,
9b86974e 61L<BN_CTX_start(3)>
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63=head1 HISTORY
64
a528d4f0 65BN_CTX_init() was removed in OpenSSL 1.1.0.
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67=head1 COPYRIGHT
68
9e183d22 69Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved.
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70
71Licensed under the OpenSSL license (the "License"). You may not use
72this file except in compliance with the License. You can obtain a copy
73in the file LICENSE in the source distribution or at
74L<https://www.openssl.org/source/license.html>.
75
76=cut