Re: [Boost-users] Get "Native" thread id - feature request

Subject: Re: [Boost-users] Get "Native" thread id - feature request
From: Rush Manbert (rush_at_[hidden])
Date: 2009-11-05 13:25:41

On Nov 5, 2009, at 10:19 AM, Rush Manbert wrote:

>
> On Nov 5, 2009, at 7:02 AM, Ondrej Sluciak wrote:
>
>>
>> Hello, is there a way how to get the thread id that system assigns  
>> to thread? I mean the id that is located in "thread_info->id". It  
>> would quite nice if boost could return this value, because for  
>> example if I want to set name of the thread on windows using  
>> function SetThreadName(), I need exactly that id.  In my  
>> application I would have to add this "feature" directly to  
>> boost::thread.hpp, which is not very nice solution.
>> I know that also GetThreadName(myThread->native_handle()) should  
>> work, but if I do it like this I always get a Windows error "The  
>> procedure entry point GetThreadId could not be located in the  
>> dynamic link library KERNEL32.dll". And I also guess, that this new  
>> "feature" wouldn't destroy the overall design of boost::thread  
>> architecture. To get the "real" thread id is in my opinion in  
>> general a useful thing.
>
>
> I'm almost ashamed to post this, but maybe it helps you.
>
> Here's a really nasty hack that I came up with to get the  
> Thread::id_t value of the thread id:

To clarify, Thread::id_t in the context of this code is typedefed as  
uint64_t, so what we're getting is just the integer value of the  
thread id.

>  Thread::id_t getId() {
>    // This is awful. The Boost::thread implementation returns a  
> thread_id class.
>    // This is the only way to extract the actual value it carries,  
> which is what a Thread::id_t
>    // wants to be. In their Windows implementation, get_id() just  
> returns an int, so we wouldn't
>    // need this junk.
>    std::stringstream ios;
>    // This needs to be a pointer because on a *nix system,  
> this_thread::get_id()
>    // returns an object that defines operator<< to write the  
> pthread_t to the stream,
>    // and it's a pointer, so it gets formatted as hex and we can't  
> change that by
>    // inserting a dec manipulator. So when we read out of the  
> stream, we need to
>    // read into something for which a hex format makes sense.
>    void *numericId;
>
>    // If this is called before start(), we're hosed
>    assert (bthread_);
>
>    ios << bthread_->get_id();
>    ios >> numericId;
>    // And, of course, static_cast can't be used to convert from  
> void* to the integer type.
>    return (Thread::id_t)numericId;
>  }
>
> - Rush_______________________________________________
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