[Spread-users] Order of members in vs_sets

John Schultz jschultz at spreadconcepts.com
Mon Mar 30 18:19:31 EDT 2009

I believe each vs_set is sorted using strcmp as the comparison.  So,
within a single vs_set I *believe* they will be sorted in ascending
order according to strcmp.

I don't know if that means you can use std::set_difference() or not
as I'm not intimately familiar with all the STL functions.


John Lane Schultz
Spread Concepts LLC
Phn: 443 838 2200 
Fax: 301 560 8875

Monday, March 30, 2009, 2:07:51 PM, you wrote:

> Dear Spread users,

> I wonder if the list of members in a vs_set, as returned by 
> SP_get_vs_set_members(), is ordered in a deterministic way. The 
> documentation for SP_receive() states that the list of members returned
> through the groups parameter (the current membership view) is the same
> for all the processes receiving the membership message, so that a leader
> can be deterministically elected for the group. Does the list of members
> is a vs_set follow the same ordering?

> In other words, can I use std::set_difference(), between 
> SP_get_vs_set_members(vs_sets[my_vs_set]) and the previous membership 
> view, to determine the members who are no longer part of the group after
> receiving a CAUSED_BY_NETWORK membership message?

> Thanks,

> Tudor

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