Question: generating v4 UUIDs

[normalscene]

Version

The version of ACE and/or TAO you are using ACE 6.5.6

Host machine and operating system

Centos 7.7

Target machine and operating system (if different from host)

Linux

Compiler name and version (including patch level)

gcc 9.2.0

The $ACE_ROOT/ace/config.h file

If you use a link to a platform-specific file, simply state which one

The $ACE_ROOT/include/makeinclude/platform_macros.GNU file

if you use a link to a platform-specific file, simply state which one (unless this isn't used in this case, e.g., with Microsoft Visual C++)

Contents of $ACE_ROOT/bin/MakeProjectCreator/config/default.features

Used by MPC when you generate your own makefiles

AREA/CLASS/EXAMPLE AFFECTED:

What example failed? What module failed to compile?

The problem effects:

Does it affect compilation, linking, or execution. Please indicate whether ACE/TAO, your application, or both are affected. NO

Synopsis

Brief description of the problem I have given the description in the comment.

Description

Detailed description of problem. Don't just say " doesn't work, here's a fix," explain what your program does to get to the state. I have explained the problem in the comment.

Repeat by

What you did to get the error; include test program or session transcript if at all possible. I am not facing any errors. I have a generic question about UUIDs.

Sample fix/ workaround

If available

This is not applicable in my case. I have a question.

[normalscene]

Hello,

I was playing around with uuid generators and observed that regardless of given version whether 1 or 4 or any other - the uuid is different only in the middle as shown below in 'Item A'.

But one uses uuidgen (which is available on linux as a binary) it produces uuids which are totally different than the previous one, as seen in 'Item B'.

Question: How can I achieve the same with ACE, any hints would be very useful. I want to generate consecutive UUIDs which are totally different compared to the last one.

Item A

(20200403-00:28:25) $:random>  ./generate_uuid.exe 
LM_INFO@00:28:27.187761@(11638|11638)@(25:main)@@ 445df0c8-76a6-41ea-8000-54e1add327e9
LM_INFO@00:28:27.187796@(11638|11638)@(25:main)@@ 445df30c-76a6-41ea-8000-54e1add327e9
LM_INFO@00:28:27.187818@(11638|11638)@(25:main)@@ 445df410-76a6-41ea-8000-54e1add327e9
(20200403-00:28:27) $:random>  

Item B

(20200403-00:30:20) $:random>  uuidgen
d1c36c2a-81c5-4c77-8927-16706e316bc7

(20200403-00:32:08) $:random>  uuidgen
6f29c915-867c-4977-a587-8e066ff44a76

(20200403-00:32:10) $:random>  uuidgen
bfb4d974-b3e2-4bd0-8c4d-44de6f016b9d

(20200403-00:32:11) $:random>  uuidgen
f32b348e-5eb7-48d4-8815-39189d058993

(20200403-00:32:12) $:random>  uuidgen
fb5e93e1-cffe-47b8-8990-217a169f35cb

[normalscene]

So I now know why the uuid "node" is always the same as it is controlled by the init function, as seen below in "ace/UUID.cpp" file in ace version 6.5.6.

Why is it not random each time? Is there a specific reason for binding it to the macaddress?

   337	  void
   338	  UUID_Generator::init (void)
   339	  {
   340	    if (this->is_init_)
   341	      return;
   342	
   343	    ACE_OS::macaddr_node_t macaddress;
   344	    int const result = ACE_OS::getmacaddress (&macaddress);
   345	
   346	    UUID_Node::Node_ID node_id;
   347	
   348	    if (-1 == result)
   349	      {
   350	        ACE_OS::memcpy (node_id,
   351	                        macaddress.node,
   352	                        UUID_Node::NODE_ID_SIZE);
   353	      }
   354	    else
   355	      {
   356	        node_id [0] = static_cast<u_char> (ACE_OS::rand ());
   357	        node_id [1] = static_cast<u_char> (ACE_OS::rand ());
   358	        node_id [2] = static_cast<u_char> (ACE_OS::rand ());
   359	        node_id [3] = static_cast<u_char> (ACE_OS::rand ());
   360	        node_id [4] = static_cast<u_char> (ACE_OS::rand ());
   361	        node_id [5] = static_cast<u_char> (ACE_OS::rand ());
   362	      }
   363