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BN_zero(3)                          OpenSSL                         BN_zero(3)



NAME
       BN_zero, BN_one, BN_value_one, BN_set_word, BN_get_word - BIGNUM
       assignment operations

LIBRARY
       libcrypto, -lcrypto

SYNOPSIS
        #include <openssl/bn.h>

        void BN_zero(BIGNUM *a);
        int BN_one(BIGNUM *a);

        const BIGNUM *BN_value_one(void);

        int BN_set_word(BIGNUM *a, BN_ULONG w);
        unsigned BN_ULONG BN_get_word(BIGNUM *a);

DESCRIPTION
       BN_ULONG is a macro that will be an unsigned integral type optimized
       for the most efficient implementation on the local platform.

       BN_zero(), BN_one() and BN_set_word() set a to the values 0, 1 and w
       respectively.  BN_zero() and BN_one() are macros.

       BN_value_one() returns a BIGNUM constant of value 1. This constant is
       useful for use in comparisons and assignment.

       BN_get_word() returns a, if it can be represented as a BN_ULONG.

RETURN VALUES
       BN_get_word() returns the value a, or all-bits-set if a cannot be
       represented as a single integer.

       BN_one() and BN_set_word() return 1 on success, 0 otherwise.
       BN_value_one() returns the constant.  BN_zero() never fails and returns
       no value.

BUGS
       If a BIGNUM is equal to the value of all-bits-set, it will collide with
       the error condition returned by BN_get_word() which uses that as an
       error value.

       BN_ULONG should probably be a typedef.

SEE ALSO
       BN_bn2bin(3)

HISTORY
       In OpenSSL 0.9.8, BN_zero() was changed to not return a value; previous
       versions returned an int.

COPYRIGHT
       Copyright 2000-2018 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
       <https://www.openssl.org/source/license.html>.



3.0.12                            2023-05-07                        BN_zero(3)