[boost] boost.threads join and join_all

From: Eyal Farago (eyalfa_at_[hidden])
Date: 2002-04-10 06:29:31

I believe there is a problem with tread_gruop::join_all() and
thread::join().

the following code fragment will raise an assertion:

boost::thread_group	tg;

tg.create_thread( ... )
...
tg.create_thread( ... )

tg.join_all()

tg.create_thread( ... )
...
tg.create_thread( ... )

tg.join_all()	//this asserts false.

I believe there are two problems here:
1. join_all does'nt clean the inner list of threads, I believe that it
can't do it since calling create_thread() returns a thread* that the
client might refer to later.
2.thread::join() ignores the m_joinable member and attempts the actual
join operation even when it should'nt do so( i.e. default constructed
threads ). The first iteration of thread_group::join_all to attempt to
join all threads in the group including those already joined earlier,
this of course fails.

I believe that number 2 is the real problem here, and it can be solved
with a simple if like the destructor does, another solution would be
exposing a joinable() method that can be accessed before calling join().

By the way I'm working on win 2k, msvc6 sp 5.

Eyal.