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 13:19:35

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:
   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