6 – Thread Pool Step 4:How to Use

This is just a quick overview onwhat you need to do to use the thread pool.
Note: In this tutorial, I’ve shown you functionsthat you need to create the thread pool. There are, however, smaller functions(accessors, mutators, etc.) that I haven’t shown you, but are easy tounderstand.
Note 2: The example project also was compiledusing VisualLeak Detector. If you try to run the sample without VLD, you’ll get acrash. Just comment out the #include in “main.cpp” or go and download the handy-dandytool.

Adding the Thread Pool To YourProject

This is also expressed in theREADME that comes with the sample project in on the download page for thisproject. Really it’s quite simple, and there are 2 ways to go about it.
Variant 1: Add the library to your project.
This method is a bit hard to getdown, but when you do it enough times, you’ll get it. And it’s always righthere to reference back to.

Cut a hole in a box

Put your j–

WHOA! Wrong instructions!
Damn you,Timberlake!
OK, here they are…

Put the libKMThreadPool folder from the sample project somewhere on your computer that’s easy to reference to (for example: “C:/C++/libKMThreadPool/”

Go to Visual Studios and open the solution that contains your project (lets call it “MyProj”)

Include the project file for libKMThreadPool into your solution

Right-click on MyProj and open Properties

In “C++>>General” under “Additional Include Directories,” add in the path to the thread pools’ directory (in this example it would be “C:/C++/libKMThreadPool/”)

Now, still in Properties, go in “Linker>>Input” under “Additional Dependencies” and add libKMThreadPool.lib

Now exit Properties, click on MyProj, and click on Project Dependencies.

Check the checkbox that reads “libKMThreadPool”

That’s all there is to it! If youcompile the project now, the output .lib file from libKMThreadPool will appearin the same directory as your solution for MyProj is in. Cool, huh?
Variant 2: Add the sourcedirectly into your project.
This is real easy. If for somereason the above method doesn’t work, then just copy all the source files fromlibKMThreadPool and chuck them directly into your project. Quick and dirty.

Initializing and Shutting Downthe Thread Pool

Including the files
The thread pool I have set up areall in namespaces. The primary namespace is kmp . The threading stuff (such as KMLock,KMThread, etc.) are all stored in kmp::threading , any Utilities are under kmp::threading::utility , and any algorithms are in kmp::threading::algorithms .
Since you included thedirectories, you won’t need some long, horrible-looking #include. The onlyfiles you’ll really be interacting with a lot are KMThreadPool_Win32.h” and“KMUtility.h” (and “KMLock.h” maybe).
Initializing
First thing’s first – when youwant to use the thread pool from anywhere, you’ve got to grab the singletoninstance of it.

KMThreadPool* pthreadpool = KMThreadPool::getInstance();

That’s easy. If you’re doing thisfrom inside a class definition, you may want to store the instance so you’renot constantly calling getInstance(). Once you have that, now it’s time to call initialize() .
But wait! I know you’re ready tocall pthreadpool->Initialize(1000, 1000000); but that would be foolish! You processordoesn’t have that much power, but it will try to create at least 1000 threads,but maybe only 4 of them will be actual threads! All the rest will be virtualthreads.
Most processors are designedonly to really allow 2 threads per core (some have been known to go as farup as 8), so reasonably, if you have a dual-core processor, your max threadsshould be 4, and min should be 2. If you try to increase that number, you’llnotice your program will run very sluggish.
Now that our thread pool isready, we can call BeginProcessing() and start adding tasks!
Shut down
Once your program is finished,it’s a good idea to clean up the memory this thread pool has allocated. Now,you can call StopProcessing() and then call Shutdown() on the thread pool, or you can just call Shutdown() . Either way, call Shutdown() once your program is finished. Done.

Adding Tasks

 Adding tasks require a bitof set up. The first thing we want to do is set up a child class of IKMTaskData . This class is going to contain dataneeded for your task, like, say, float fElapsedTime , int Index , GameObject* curObj , etc, etc. See the examples in the sampleproject if you need more explanation, but there really isn’t much to explain here.
Now for the task function itself.Remember: the task function must be static, as explained in Step 2. This taskmust be set up just like KMTaskFunc – same return value, same parameter list. If youwant to access your data you made in the child of IKMTaskData from the IKMTaskData* , you have to cast the IKMTaskData* to your child class, also as explained inStep 2.
So lets say we have voidMyTask(IKMTaskData*) and MyTaskData which derives from IKMTaskData and contains 2 ints and a constructor. How do I getthis to the pool?

pthreadpool->AddTask(MyTask, new MyTaskData(10, 67));

Easy.
変換元:http://keithmaggio.wordpress.com/code/c-win32-thread-pool-manager/6-step4/