Re: [Boost-users] Does lock-less queue wait on empty queue ?

Subject: Re: [Boost-users] Does lock-less queue wait on empty queue ?
From: Leon Mlakar (leon_at_[hidden])
Date: 2015-05-19 16:47:32

On 19.05.2015 03:28, Gavin Lambert wrote:
> On 19/05/2015 01:02, Sebastian Messerschmidt wrote:
>> Am 18.05.2015 um 13:51 schrieb Ran Shalit:
>>> Hello,
>>>
>>> I'm newbie of boost library.
>>>
>>> I would like to ask if the lockless queue waits on empty queue ? (I
>>> actually need it to wait).
>> You can easily wait yourself, and everyone would want to wait
>> differently, so there is no point in putting into the queue's
>> implementation.
>> For instance you could give up your scheduler time-slice, or you might
>> want to spin-lock
>>
>> while(!queue.pop(my_data))
>> {
>>        boost::this_thread::yield(); //give up time slice
>> }
>
> You can also do a "real" wait until something has been pushed (which 
> can be important as yield() does not let lower-priority threads run), 
> but currently doing that requires using either Win32 events or using 
> condition variables -- but the latter requires adding a mutex on both 
> ends, which may defeat the point of using a lock-free queue in the 
> first place.
>
>
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It would be an interesting exercise to integrate lock-less queue with 
libdispatch or similar open source event library. But then again, with 
task queues like those of libdispatch  around you may be able avoid 
multi-threading issues in first place.

Leon