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Subject: [boost] [thread] possible raise in future?
From: Oliver Kowalke (oliver.kowalke_at_[hidden])
Date: 2013-02-03 07:04:49

Hello Vicente,

after analyzing the code of future<> from boost.thread I think the code
might contain raise condition.
future.hpp:226: future_object_base defined 'bool done'.
future_object_base::mark_finished_internal() sets 'done' tot true (line
308) and future_object_base::wait_internal()
reads it (line 347).
Shouldn't 'done' be of type atomic<bool >? I believe that the compiler can
reorder the usage of 'done' and two
threads (writer thread calling make_finished_internal() and reader calling
wait_internal()) might see different values.
At least I think it might be possible that some thread will always be
waiting in waiters.wait() (line 349), because
the write r thread sets done=true and call waiters.notify_all() and a
reader thread calls later wait_internal() but does not
see that done is true because of memory reordering etc. and will be blocked
in waiters.wait()forever.

What do you think?

best regards,

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