On 2004-10-01, Parameswaran, Vinod <vparameswaran@fcg.com> wrote:
2. Does anyone have some examples of scenarios wherein each of these classes could be used (would even appreciate reference to relevant docs., if any):
a. barrier
Never used this.
b. condition
This can be used to broadcast things to other groups - a thread might want to wait for a number of events to become available for example
c. thread_group
This is a boost concept which allows one to wait on several threads simultaneously - pretty well documented.
d. thread_specific_ptr
I didn't know boost threads provided this. Consider this function: char *getSomething(int var) { static buffer[12]; // do stuff that fills buffer return buffer; } This is fine in a singlethreaded world but you enter a world of pain if you do this in an environment where other threads might be calling getSomething at the same time - there is only 1 buffer[12] to work with, and all of them will scribble it at the same time! Thread specific storage makes sure that each thread has its own static storage.
3. Assumption: In the case of a condition object, ONLY THE FOLLOWING METHODS could be used to specify the wait condition: (...) Is this correct?
Beyond me.
4. <begin quote> A thread object has an associated state which is either "joinable" or "non-joinable". <end quote>
Is this state indicated using a type or is merely implied by whether the default or the parameterized constructor is called for the creation of the thread object?
A thread can detach itself and become non-joinable. This saves memory. I think a thread group manages this for you.
5. Could anyone give examples of the use of void join() and void yield()? (Would even appreciate reference to relevant docs., if any)
SProxyListener nl; boost::thread* thr=threads.create_thread(boost::bind(&SProxyListener::run, &nl)); thr->join(); This is from a real program. Yield() has somewhat varying semantics but generally means 'give up this timeslice'. When busywaiting on something, yield() yields the CPU to other threads or processes.
6. <begin quote> Template thread_specific_ptr stores a pointer to an object obtained via new on a thread-by-thread basis and calls delete on the contained pointer when the thread terminates. Each thread initially stores the null pointer in each thread_specific_ptr instance.
No idea. I haven't been able to answer all your questions but I hope this helped enough. Good luck. -- http://www.PowerDNS.com/ Open Source Database Driven Nameserver http://lartc.org Linux Advanced Routing & Traffic Control HOWTO