Re: Use of TerminateThread Function

On Dec 1, 9:44 pm, "Michel Verhagen (eMVP)" <mic...@xxxxxxxxxx> wrote:
The preferred way to exit is of course graceful. TerminateThread doesn't
clean up any resources allocated by the thread it's terminating and so
using TerminateThread could result in memory leaks.

Your while loop seems a bit strange... Why not use an event? That is
much more efficient; it won't use up any CPU ticks until the event is
set, and it will allow you to exit immediately instead of having to wait
up to 1000 ms before the thread exits:

DWORD WINAPI MyThread(LPVOID lpParameter)
{
   HANDLE hEvent = (HANDLE)lpParameter;

   LPBYTE buffer = new BYTE[100];
   for (;;)
   {
       if (WAIT_OBJECT_0 == WaitForSingleObject(hEvent, INFINITE))
       {
           // Check if event was set by application exit code
           if (GetEventData(hEvent))
                break;
           // Do normal operation
           memcpy(buffer, "lalalalala", 10);
       }
       else
           break;
   }

   // Clean up any resources you allocated in this thread
   delete []buffer;

   return 0;

}

Your application would create the thread and the event like this:

HANDLE hEvent = CreateEvent(NULL, FALSE, FALSE, NULL);
SetEventData(hEvent, FALSE);  // Indicate normal operation
HANDLE hThread = CreateThread(NULL, 0, MyThread, (LPVOID)hEvent, 0, NULL);

In this example I'm using Set/GetEventData to set/determine if this is a
normal event or an "exit" event.

To kick the thread to do it's normal operation you'd:

SetEvent(hEvent);

To stop the thread gracefully you'd execute the following code:

SetEventData(hEvent, TRUE);  // Indicate thread needs to exit
SetEvent(hEvent);

// Give the thread 1 second to exit gracefully, otherwise terminate
if (WAIT_TIMEOUT == WaitForSingleObject(hThread, 1000))
    TerminateThread(hThread, 1);

// And clean up
CloseHandle(hEvent);
CloseHandle(hThread);

Good code will never execute the TerminateThread line! If you have to
terminate a thread it's time for some code review...

(Note that it's also not good practice to assume LPVOID can hold a
HANDLE, but for simplicity sake I've used it in this example.)

PS. I did not compile this code!

Good luck,

Michel Verhagen, eMVP
Check out my blog:http://GuruCE.com/blog

 GuruCE
 Microsoft Embedded Partner
 http://GuruCE.com
 Consultancy, training and development services.

Raj wrote:
Hi All,

I am working on an app in WM 6.1 and there is a thread that is
sleeping in a while loop until some condition is met.
If I satisfy the condition and then exit out of the application it is
working fine for me but if I don't the exit is giving me prefetch
abort while unloading the DLL.

When I am explicitly terminating the thread before unloading the DLL
in some DeInit function it is working fine but otherwise don't.

I have one question is it advisable to use TerminateThread.I know the
code the thread will be executing when I will terminate the thread.

So basically it is the while loop that is causing the prefetch abort
when I am exiting out without satisfying the condition.

the loop is very simple.

while(x==y)
{
   Sleep(1000);
}

where y is default behavior.

Appreciate any help.

Raj

Thanks Michel,C.L.

The code is same both for the application(*.EXE) and the DLL (Control
Panel Applet (*.CPL)).

I am not sure Michel,when the application exits I mean the EXE it just
exits gracefully but when the application(Control Panel Applet *.CPL
(In turn Dll)) exits it just gives the prefetch abort because the
thread is in this while loop.

I tried the event options but it didn't work may be I need to review
the code again and give it another try.

Anyways Michel really appreciated your help.

Raj


.

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