Bug 17

Summary:	possible compiler bug causing loss of tags registry information
Product:	ns-3	Reporter:	Gustavo J. A. M. Carneiro <gjcarneiro>
Component:	core	Assignee:	Mathieu Lacage <mathieu.lacage>
Status:	RESOLVED FIXED
Severity:	blocker
Priority:	P1
Version:	pre-release
Hardware:	PC
OS:	Linux
Attachments:	the patch

Description Gustavo J. A. M. Carneiro 2007-04-16 13:00:37 UTC

Basically, after some hours of debugging i discovered that TagRegistry::m_registry was being initialized twice in the same program, causing loss of information added to it before the second initialization.  I suspect a compiler bug, but in any case it was very easy to work around it by lazy-initializing the vector.  I committed a patch to my tree; feel free to include it upstream if you want.

Comment 1 Gustavo J. A. M. Carneiro 2007-04-16 13:01:10 UTC

Created attachment 10 [details]
the patch

Comment 2 Mathieu Lacage 2007-04-18 02:19:21 UTC

I would like to see a test-case which shows the bug first. i.e., if you are willing to send me the code, I can look into this.

Comment 3 Mathieu Lacage 2007-04-19 04:59:06 UTC

I have pushed a similar although more complete patch to lazyly initialize m_sorted too. The real issue here I think is that this code could be subject to static variable initialization order problems which might have looked like a double initialization problem to you. 

So, it would be nice to get some testing feedback on the version I pushed. Marking bug as fixed.