BN_zero.pod revision 331638 
1=pod
2
3=head1 NAME
4
5BN_zero, BN_one, BN_value_one, BN_set_word, BN_get_word - BIGNUM assignment
6operations
7
8=head1 SYNOPSIS
9
10 #include <openssl/bn.h>
11
12 int BN_zero(BIGNUM *a);
13 int BN_one(BIGNUM *a);
14
15 const BIGNUM *BN_value_one(void);
16
17 int BN_set_word(BIGNUM *a, BN_ULONG w);
18 BN_ULONG BN_get_word(BIGNUM *a);
19
20=head1 DESCRIPTION
21
22B<BN_ULONG> is a macro that will be an unsigned integral type optimied
23for the most efficient implementation on the local platform.
24
25BN_zero(), BN_one() and BN_set_word() set B<a> to the values 0, 1 and
26B<w> respectively.  BN_zero() and BN_one() are macros.
27
28BN_value_one() returns a B<BIGNUM> constant of value 1. This constant
29is useful for use in comparisons and assignment.
30
31BN_get_word() returns B<a>, if it can be represented as a B<BN_ULONG>.
32
33=head1 RETURN VALUES
34
35BN_get_word() returns the value B<a>, or all-bits-set if B<a> cannot
36be represented as a B<BN_ULONG>.
37
38BN_zero(), BN_one() and BN_set_word() return 1 on success, 0 otherwise.
39BN_value_one() returns the constant.
40
41=head1 BUGS
42
43If a B<BIGNUM> is equal to the value of all-bits-set, it will collide
44with the error condition returned by BN_get_word() which uses that
45as an error value.
46
47B<BN_ULONG> should probably be a typedef.
48
49=head1 SEE ALSO
50
51L<bn(3)|bn(3)>, L<BN_bn2bin(3)|BN_bn2bin(3)>
52
53=head1 HISTORY
54
55BN_zero(), BN_one() and BN_set_word() are available in all versions of
56SSLeay and OpenSSL. BN_value_one() and BN_get_word() were added in
57SSLeay 0.8.
58
59BN_value_one() was changed to return a true const BIGNUM * in OpenSSL
600.9.7.
61
62=cut
63