BN_zero, BN_one, BN_value_one, BN_set_word, BN_get_word - BIGNUM assignment operations
#include <openssl/bn.h>
int BN_zero(BIGNUM *a); int BN_one(BIGNUM *a);
const BIGNUM *BN_value_one(void);
int BN_set_word(BIGNUM *a, BN_ULONG w); BN_ULONG BN_get_word(BIGNUM *a);
BN_ULONG is a macro that will be an unsigned integral type optimied 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.
BN_get_word() returns the value a, or all-bits-set if a cannot
be represented as a BN_ULONG.
BN_zero(), BN_one() and BN_set_word() return 1 on success, 0 otherwise.
BN_value_one() returns the constant.
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.
BN_zero(), BN_one() and BN_set_word() are available in all versions of
SSLeay and OpenSSL. BN_value_one() and BN_get_word() were added in
SSLeay 0.8.
BN_value_one() was changed to return a true const BIGNUM * in OpenSSL
0.9.7.