NAME

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

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>.