I strongly disagree with such policy. For example, when I try to find a solution for a problem on the internet, such as an compiler warning or error, and I see threads marked as solved, it is very likely that that threat is worth reading.
It also avoids people trying to help read a thread that is already solved, thus enabling them not to waste time.
Probably the forum administrators don't want people to change the contents of thread after answers have been made to it, because answers might lose their context. It this case, a 'Mark thread as solved' could be implemented in the Thread Tools.
I go for the "solved" threads first too, and it is a good general indicator. But there are some pitfalls: namely, it's not unusual for someone to believe their problem is solved when it isn't.
I think the ideal solution would be to have a tick box so the OP could mark a thread as solved pending moderator approval. Unfortunately, I've never seen such a system anywhere, so I doubt it exists for vBulletin. Seems like a good suggestion for them tho.
I don't think that would be a serious problem, and a "solved" thread should not be a closed thread. Even if the specific problem really is solved, there could be value in further comments.Probably the forum administrators don't want people to change the contents of thread after answers have been made to it, because answers might lose their context.
C programming resources:
GNU C Function and Macro Index -- glibc reference manual
The C Book -- nice online learner guide
Current ISO draft standard
CCAN -- new CPAN like open source library repository
3 (different) GNU debugger tutorials: #1 -- #2 -- #3
cpwiki -- our wiki on sourceforge