Re: Memory leak after closing thread.

From:
peter koch <peter.koch.larsen@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Tue, 8 Dec 2009 14:56:30 -0800 (PST)
Message-ID:
<3924c821-d613-489b-9ada-d155c378cd22@u7g2000yqm.googlegroups.com>
On 1 Dec., 16:07, Michal <mmatuszewski...@gmail.com> wrote:

Before I explain exactly where is the problem I will show my code:
(Platform - Windows CE 5, VisualStudio 2005)

The interesting part of source code is below:

/**************************************************************/
class classA {
        public:
        static DWORD WINAPI testingThread(LPVOID lpvoid);
        HANDLE m_hThread;
        void startthread();

};

DWORD WINAPI classA::testingThread(LPVOID lpvoid)
{
        return 1;

}

void classA::startthreadk()
{
        for(int counter = 0 ; counter < 100 ; counter++) {
                MEMORYSTATUS memInfo;
                memInfo.dwLength = sizeof(memInfo);
                GlobalMemoryStatus(&memInfo);
                DWORD dwThreadId = 0;
                m_hThread = CreateThread(NULL, 0, testi=

ngThread, this,

0,
&dwThreadId);
                DWORD dwRet = WaitForSingleObject(m_hTh=

read,

INFINITE);
                if(WAIT_OBJECT_0 != dwRet) {
                        TRACE(_T("Something wrong=

 !!! \n"));

                }
                int returnHandle = CloseHandle(m_hThrea=

d);

                TRACE(_T("After closing handle = %d
\n"),returnHandle);
                m_hThread = NULL;
                MEMORYSTATUS memInfo1;
                memInfo1.dwLength = sizeof(memInfo1);
                GlobalMemoryStatus(&memInfo1);
                TRACE(_T("%d Test %d\n"),counter, memInfo=

..dwAvailPhys

-
memInfo1.dwAvailPhys);
        }

}

/**************************************************************/

The problem is that I don't know why but sometimes (usually one per
three times)
I can see the memory leak of 4096 bytes. Why? Do I do something wrong
with closing
thread? (Of course the program without creating thread works ok).
Closehandle
always returns 1, so everything should be ok.

I will be grateful for any response.

Michal


Three comments: First as Michael Tsang noted, this is Windows-specific
code: you are more likely to get an appropriate response there.
Secondly: if you increase the loop-count, does the memory usage
continue to grow? If not, oyu probably don't have a leak.
Last: You get a handle - don't you have to release it? Which takes me
back to the first point - ask in a Windows group. But read the
documentation first.

/Peter

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