Add documentation for CRYPTO_memcmp.

[openssl.git] / doc / man3 / BN_zero.pod

diff --git a/doc/man3/BN_zero.pod b/doc/man3/BN_zero.pod
index 91d48aad880862e1520046f8395c1c09574a5d70..ca8d7b5dc6efc1684e036230fa002b4d0d736902 100644 (file)
--- a/doc/man3/BN_zero.pod
+++ b/doc/man3/BN_zero.pod
@@ -14,52 +14,53 @@ operations
 
  const BIGNUM *BN_value_one(void);
 
- int BN_set_word(BIGNUM *a, unsigned long w);
- unsigned long BN_get_word(BIGNUM *a);
-
-Deprecated:
-
- #if OPENSSL_API_COMPAT < 0x00908000L
- int BN_zero(BIGNUM *a);
- #endif
+ int BN_set_word(BIGNUM *a, BN_ULONG w);
+ unsigned BN_ULONG BN_get_word(BIGNUM *a);
 
 =head1 DESCRIPTION
 
+B<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 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 single integer.
 
-BN_one(), BN_set_word() and the deprecated version of BN_zero()
-return 1 on success, 0 otherwise.
+BN_one() and BN_set_word() return 1 on success, 0 otherwise.
 BN_value_one() returns the constant.
-The preferred version of BN_zero() never fails and returns no value.
+BN_zero() never fails and returns no value.
 
 =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
 
 L<BN_bn2bin(3)>
 
+=head1 HISTORY
+
+In OpenSSL 0.9.8, BN_zero() was changed to not return a value; previous
+versions returned an int.
+
 =head1 COPYRIGHT
 
-Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved.
+Copyright 2000-2018 The OpenSSL Project Authors. All Rights Reserved.
 
-Licensed under the OpenSSL license (the "License").  You may not use
+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
 L<https://www.openssl.org/source/license.html>.