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-rw-r--r--doc/crypto/BN_zero.pod21
1 files changed, 12 insertions, 9 deletions
diff --git a/doc/crypto/BN_zero.pod b/doc/crypto/BN_zero.pod
index b555ec398859..8aa9c142b725 100644
--- a/doc/crypto/BN_zero.pod
+++ b/doc/crypto/BN_zero.pod
@@ -14,34 +14,37 @@ operations
const BIGNUM *BN_value_one(void);
- int BN_set_word(BIGNUM *a, unsigned long w);
- unsigned long BN_get_word(BIGNUM *a);
+ int BN_set_word(BIGNUM *a, BN_ULONG w);
+ BN_ULONG BN_get_word(BIGNUM *a);
=head1 DESCRIPTION
+B<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 B<a> to the values 0, 1 and
B<w> respectively. BN_zero() and BN_one() are macros.
BN_value_one() returns a B<BIGNUM> constant of value 1. This constant
is useful for use in comparisons and assignment.
-BN_get_word() returns B<a>, if it can be represented as an unsigned
-long.
+BN_get_word() returns B<a>, if it can be represented as a B<BN_ULONG>.
=head1 RETURN VALUES
-BN_get_word() returns the value B<a>, and 0xffffffffL if B<a> cannot
-be represented as an unsigned long.
+BN_get_word() returns the value B<a>, or all-bits-set if B<a> cannot
+be represented as a B<BN_ULONG>.
BN_zero(), BN_one() and BN_set_word() return 1 on success, 0 otherwise.
BN_value_one() returns the constant.
=head1 BUGS
-Someone might change the constant.
+If a B<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.
-If a B<BIGNUM> is equal to 0xffffffffL it can be represented as an
-unsigned long but this value is also returned on error.
+B<BN_ULONG> should probably be a typedef.
=head1 SEE ALSO