=pod
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=head1 NAME
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BN_zero, BN_one, BN_value_one, BN_set_word, BN_get_word - BIGNUM assignment
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operations
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=head1 SYNOPSIS
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#include <openssl/bn.h>
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void BN_zero(BIGNUM *a);
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int BN_one(BIGNUM *a);
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const BIGNUM *BN_value_one(void);
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int BN_set_word(BIGNUM *a, BN_ULONG w);
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unsigned BN_ULONG BN_get_word(BIGNUM *a);
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=head1 DESCRIPTION
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B<BN_ULONG> is a macro that will be an unsigned integral type optimized
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for the most efficient implementation on the local platform.
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BN_zero(), BN_one() and BN_set_word() set B<a> to the values 0, 1 and
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B<w> respectively. BN_zero() and BN_one() are macros.
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BN_value_one() returns a B<BIGNUM> constant of value 1. This constant
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is useful for use in comparisons and assignment.
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BN_get_word() returns B<a>, if it can be represented as a B<BN_ULONG>.
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=head1 RETURN VALUES
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BN_get_word() returns the value B<a>, or all-bits-set if B<a> cannot
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be represented as a single integer.
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BN_one() and BN_set_word() return 1 on success, 0 otherwise.
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BN_value_one() returns the constant.
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BN_zero() never fails and returns no value.
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=head1 BUGS
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If a B<BIGNUM> is equal to the value of all-bits-set, it will collide
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with the error condition returned by BN_get_word() which uses that
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as an error value.
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B<BN_ULONG> should probably be a typedef.
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=head1 SEE ALSO
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L<BN_bn2bin(3)>
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=head1 HISTORY
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In OpenSSL 0.9.8, BN_zero() was changed to not return a value; previous
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versions returned an int.
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=head1 COPYRIGHT
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Copyright 2000-2018 The OpenSSL Project Authors. All Rights Reserved.
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Licensed under the OpenSSL license (the "License"). You may not use
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this file except in compliance with the License. You can obtain a copy
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in the file LICENSE in the source distribution or at
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L<https://www.openssl.org/source/license.html>.
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=cut
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