11th Chapter Windows thread Pool (1) _ Traditional Windows thread pool

11th Chapter Windows thread pool

11.1 traditional Windows thread pool and API

11.1.1 traditional thread pool objects and their corresponding APIs

Thread Pool object	API
Normal task thread pool	QueueUserWorkItem
Timer thread pool	Createtimerqueue (create thread pool)
	Createtimerqueuetimer (create timer)
	Changetimerque Uetimer
	Deletetimerqueuetimer
	Detetimerqueueex
Synchronization object wait thread pool	Regist Erwaitforsingleobject
	Unregisterwaitex
Complete port thread pool	Bindiocompletioncallback

11.1.2 Common task thread pool

(1) QueueUserWorkItem function

ULONG Flags

parameters	description
Lpthread_start_routine Pfncallback	Work item, which is a callback function that is queued to the thread pool (similar to a thread function), the prototype is declared DWORD WINAPI ThreadProc (LPVOID lpparameter);
PVOID Context	Additional data to pass to the thread function
is used to indicate under what conditions a thread in a thread pool calls this callback function ①wt_ Executedefault: Normal threads do not operate in a warning state. ②wt_executeiniothread: Runs the thread callback function in an IO-warning state. ③wt_executeinpersistentthread: The thread has been running without terminating. ④wt_executelongfunction: Performs a long-running task (which causes the system to consider whether to create new threads in the thread pool). ⑤wt_transfer_impersonation: Run the thread with the current access token and callback function
Note: The CreateThread function is consistent with the prototype of the threading function required by the QueueUserWorkItem function. Therefore, it is convenient to create a thread function as a thread pool callback function for threads or pool.

"QueueUserWorkItem Sample Program"

#include <windows.h>#include<locale.h>#include<tchar.h>#include<strsafe.h>#defineBeginthread (Fun,param) CreateThread (null,0, (lpthread_start_routine) fun,param,0,null);DWORD WINAPI ThreadProc (LPVOID lpparameter);int_tmain () {_tsetlocale (Lc_all, _t ("CHS")); intIwaitlen =0;  Do{_tprintf (_t ("Please enter a waiting time constant, in seconds (enter 0 to exit):")); _tscanf_s (_t ("%i"), &Iwaitlen); if(iwaitlen>0){            //The following code demonstrates that using CreateThread and QueueUserWorkItem, the actual effect//is the same, of course, if there are not many threads, be sure to use QueueUserWorkItem if there are many threadsQueueUserWorkItem (ThreadProc, (PVOID) Iwaitlen, wt_executelongfunction); //display the effect of using CreateThread to create multiple threads//Beginthread (ThreadProc, (LPVOID) iwaitlen);        }    }  while(Iwaitlen); return 0;}//The function can be started by a thread of createthread, or it can be started using a thread in the QueueUserWorkItem thread poolDWORD WINAPI ThreadProc (lpvoid lpparameter) {intIwaitlen = (int) Lpparameter; _tprintf (_t ("\ nthe thread [id:0x%x] will wait for%u seconds ..."), GetCurrentThreadID (), Iwaitlen); Sleep (Iwaitlen* +); _tprintf (_t ("\ nthe thread [id:0x%x] will wait for the end! \ n"), GetCurrentThreadID (), Iwaitlen); return 0;}

11th Chapter Windows thread Pool (1) _ Traditional Windows thread pool