Damien McGivern wrote:

(First post) Hi, I've just started working with boost and have come into some trouble with the thread class. I've included the test code that I'm having the problem with in the hope that someone could point out to me where I'm going wrong.

The code tests the QueueAccessor class (CommandQueue.hpp) with the test code in CommandQueueTest.hpp. I created a base class (Runnable) to aid in creating a thread that runs an object's method rather than a function. The code compiles OK and seems to run OK too at first until I realised that the main thread has somehow become one of the threads that I created and is in a continuous loop after the first join() is called

_writer_thread1->join(); // line 21

join() waits for the thread to *end*. This should be done after the threads have been told to Stop().

As you can probably guess from my code my background is in Java so I'm not entirely sure if I'm using the boost::thread correctly.

I thought Java's join() was exactly the same.

I tested the QueueAccessor using threads that use a static worker function instead of an object's method and it seemed to run OK so I'm assuming that the problem lies with the Runnable base class.

I'm using boost version 1.31.0 running Windows XP and using VS.Net 2003 to compile/run the code.

Any help will be very much appreciated

Here are the bugs I found: - Runnable::_running is read and written from multiple threads without use of a mutex. - The result of QueueAccessor::Pop is undefined if the queue is empty. Perhaps it should throw in this case? - The return type of QueueAccessor::Size should be std::queue<QueueItem>::size_type (which I think is std::size_t). - QueueAccessor::Size doesn't lock the mutex for the queue. - Reader::Do busy-waits for input. It should wait on a condition variable instead. (Condition variables provide functions equivalent to the wait, notify and notifyAll methods that Object has in Java.) Worse, when the reader is asked to stop, Reader::Do may never return to Worker::Run and so the thread will never stop. - CommandQueueTest.hpp doesn't include <iostream>. - #include <name> is reserved for use with system headers. You should use #include "name" for including your own headers. - Identifiers that include "__" are reserved for the use of the implementation. You must not use them. - Many member variables are protected when they should be private. I have fixed most of the above and the program now works. Ben.