Re: [Boost-users] Several novice questions concerning threading

Subject: Re: [Boost-users] Several novice questions concerning threading
From: Master (master.huricane_at_[hidden])
Date: 2012-04-11 12:43:17

thank you i just replied back :) it just conisided :)
thank you for the explanation . iam just a beginner those information are
indeed valuable to me , specially any kind of book demonstrating threading
capabilities as much as possible .:)

On Wed, Apr 11, 2012 at 8:06 PM, Ovanes Markarian <om_boost_at_[hidden]>wrote:

> Hello Master,
>
> (sounds a bit weired if you ask beginners questions ;)
>
> On Wed, Apr 11, 2012 at 5:08 PM, Vicente J. Botet Escriba <
> vicente.botet_at_[hidden]> wrote:
>
>>  Le 11/04/12 13:31, Master a écrit :
>>
>> Hello all .
>> i am a newbie to the boost community . i recently started learning about
>> threads in boost . now there are some questions i would like to ask :
>>
>> Welcome.
>>
>>  1.where can i find examples showing practical uses of boost::thread
>> features?
>>
>> The documentation doesn't contains too much examples. You can take a look
>> at the libs/thread/example and tutorial directories :(
>>
>
> I would suggest reading Anthony's book on C++ concurrency. The threads in
> C++11 were modeled after Boost.Threads and Anthony gave the Boost.Threads
> library a major rewrite. Here is a link to it:
> http://www.manning.com/williams/ This book contains lots of examples
> which are explained in great detail.
>
>  2.how can i get all threads ID issued by me in my app?
>>
>> No direct way other that storing them in a container. What is your use
>> case?
>>
>
>>  3.how can i iterate through running threads in my app ?
>>
>> No direct way other than storing a thread pointer in a container. What is
>> your use case?
>>
>>  4.is there any kind of means to get all the running threads using boost
>> library? if it does whats the calss? if it doesnt how can i do that?
>>
>> See above. I think that you need to specialize the thread class so that
>> it inserts a handle to the created thread on a container at construction
>> time and remove it at destruction time.
>>
>>  5.can i resume a thread after pausing it ? ( how can i pause a thread? )
>>
>> Boost.Thread doesn't provide fibers or resumable threads. There is
>> Boost.Fiber for that purpose (not yet in Boost).
>>
>
> Just some thought on that... He did not directly ask about fibers...
> Pausing threads is considered a fragile design and bad practice. What
> happens if the thread holding a mutex is paused and the thread which should
> resume it, wants a mutex => deadlock... For example, newer .NET Framework
> versions depricated pause/resume functionality because of such behavior.
>
>
>>  6. how can i share a variable between two or more threads , suppose i
>> have a loop , i want two threads to simultaneously iterate through it , if
>> thread1 counted to 3, thread2 continues it from 4 and so on . ?
>> i already tried
>>
>> You need to protect the access to the loop index variable 'i' with a
>> mutex as you did with sum.
>>
>> HTH,
>> Vicente
>>
>>
> Best Regards,
> Ovanes
>
>>   ------
>>
>>> what is wrong with my sample app ?
>>> #include <iostream>
>>> #include <boost/thread.hpp>
>>> using namespace std;
>>> using namespace boost;
>>>
>>> mutex bmutex;
>>> int i=0;
>>> int sum=0;
>>> void IteratorFunc(int threadid)
>>> {
>>>              for (  ; i<25 ; i++)
>>>             {
>>>                     lock_guard<mutex> locker(bmutex);
>>>
>>> cout<<"\t"<<threadid<<"\t"<<this_thread::get_id()<<"\t"<<i<<"\n";
>>>                       sum+=i;
>>>             }
>>> }
>>>
>>> int main()
>>> {
>>>     //boost::posix_time::ptime start =
>>> boost::posix_time::microsec_clock::local_time();
>>>
>>>     thread thrd(IteratorFunc,1);
>>>     thread thrd2(IteratorFunc,2);
>>>
>>>     cout<<sum;
>>>     thrd.join();
>>>     thrd2.join();
>>> }
>>>
>>
>
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