Re: waiting for another thread without blocking resources...

Cholo Lennon <>
Thu, 14 Feb 2008 08:15:03 -0800 (PST)
On Feb 14, 12:57 pm, Lars Uffmann <> wrote:

Cholo Lennon wrote:

AFAIK 2 possibilities:
2- Your thread is not 'joinable'. Threads are joinable if they are
built with a ctor functor parameter (you will get an assert calling
'join' on a non-joinable thread)

Yes, I do construct it with a function parameter, I was told this is the
only way to construct a thread? In the meantime I've also seen the
reset-function, so I am very confused now... So how do I make a joinable
thread? Construct it with thread:thread() and then call thread::reset
(functor parameter)?

The boost thread documentation is not the best (lacks of basic
examples). Try looking the source code examples provided by the
library (looking the underlaying implementation is a good idea too;
It's straightforward if you know win threads or pthreads)

Well - I don't know either... Guess I'll have to get a hardcopy of some

Best Regards & Thanks for your help so far...


Take a look to thread's ctors:


    : m_joinable(false)
    m_thread = reinterpret_cast<void*>(GetCurrentThread());
    m_id = GetCurrentThreadId();
#elif ...

// explicit ctor
thread::thread(const function0<void>& threadfunc)
    : m_joinable(true)
    thread_param param(threadfunc);
    m_thread = reinterpret_cast<void*>(
        0, 0, &thread_proxy, &param, 0, &m_id));

    if (!m_thread)
        throw thread_resource_error();


If you provide a functor, you are constructing a 'joinable' thread.
Ctor without parameter constructs a thread that take the ownership of
the calling thread (this is useful in some situations).

Another way is (as Yannick told you) to use a condition (synchronized
flag). You must wait for a 'set' condition (the 'exit' thread
condition). On the ground, condition::wait calls the same function
than thread::join to perform the wait operation.


PS: Could you provide some code to check the library use?

Cholo Lennon

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