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54 lines
1.4 KiB
Plaintext
54 lines
1.4 KiB
Plaintext
=pod
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=head1 NAME
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BN_CTX_new, BN_CTX_init, BN_CTX_free - allocate and free BN_CTX structures
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=head1 SYNOPSIS
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#include <openssl/bn.h>
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BN_CTX *BN_CTX_new(void);
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void BN_CTX_init(BN_CTX *c);
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void BN_CTX_free(BN_CTX *c);
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=head1 DESCRIPTION
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A B<BN_CTX> is a structure that holds B<BIGNUM> temporary variables used by
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library functions. Since dynamic memory allocation to create B<BIGNUM>s
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is rather expensive when used in conjunction with repeated subroutine
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calls, the B<BN_CTX> structure is used.
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BN_CTX_new() allocates and initializes a B<BN_CTX>
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structure. BN_CTX_init() initializes an existing uninitialized
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B<BN_CTX>.
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BN_CTX_free() frees the components of the B<BN_CTX>, and if it was
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created by BN_CTX_new(), also the structure itself.
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If L<BN_CTX_start(3)|BN_CTX_start(3)> has been used on the B<BN_CTX>,
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L<BN_CTX_end(3)|BN_CTX_end(3)> must be called before the B<BN_CTX>
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may be freed by BN_CTX_free().
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=head1 RETURN VALUES
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BN_CTX_new() returns a pointer to the B<BN_CTX>. If the allocation fails,
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it returns B<NULL> and sets an error code that can be obtained by
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L<ERR_get_error(3)|ERR_get_error(3)>.
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BN_CTX_init() and BN_CTX_free() have no return values.
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=head1 SEE ALSO
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L<bn(3)|bn(3)>, L<err(3)|err(3)>, L<BN_add(3)|BN_add(3)>,
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L<BN_CTX_start(3)|BN_CTX_start(3)>
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=head1 HISTORY
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BN_CTX_new() and BN_CTX_free() are available in all versions on SSLeay
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and OpenSSL. BN_CTX_init() was added in SSLeay 0.9.1b.
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=cut
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