BN_CTX_get() returns a pointer to the B<BIGNUM>, or B<NULL> on error.
Once BN_CTX_get() has failed, the subsequent calls will return B<NULL>
as well, so it is sufficient to check the return value of the last
BN_CTX_get() returns a pointer to the B<BIGNUM>, or B<NULL> on error.
Once BN_CTX_get() has failed, the subsequent calls will return B<NULL>
as well, so it is sufficient to check the return value of the last