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From: Adrian Mawbey (adrian.mawbey_at_[hidden])
Date: 2005-06-13 18:23:44

Hi folks.

Apologies if this has been discussed frequently before.

I'm puzzled as to why the boost.thread thread_proxy function catches all
exceptions and then quietly ends the thread.

For example:-

class MyThreadFunctor
    void operator()() const
        // Do some processing...
        throw very_bad_exception();
        // ...never get to do some processing.

int main(int argc, char * argv[])
    MyThreadFunctor my_functor;
    boost::thread my_thread(my_functor);
    // Do lots of processing and then join to my_thread.
    // ...

In boost 1.32, the exception that is thrown in the created thread is caught in
the library's thread_proxy function and then the thread exits quietly.

Is there a compelling reason for this behaviour?

>From my point of view, it seems more flexible to not catch exceptions in
the thread_proxy function. If I wanted to, I could still get the current
behaviour by putting a try/catch-all block in the operator() function.

I would have expected the normal C++ uncaught exception actions (i.e. calling
terminate()) to occur if an exception is thrown out of the user provided
thread code.

I noticed this when (oh horror!) an error in my code threw an exception out of
operator(). I could have identified where the problem was from the core file
or Dr Watson log that would have been created if the exception had not been
caught by thread_proxy().

Am I missing something obvious here?


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