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It is possible that the thread actually finishes/terminates between the if and the join but it won't cause an error. Even if the thread terminates the kernel maintains the thread handle and/or a result object (with the thread exit code) that can be waited (and queried for the exit code). If the thread has already terminated when you call join then join returns immediately without problems.
EDIT: some additional qotes from http://en.cppreference.com/w/cpp/thread/thread/joinable[^]
"A thread that has finished executing code, but has not yet been joined is still considered an active thread of execution and is therefore joinable."
On windows (Winapi thread functions) you can have multiple handles to the same thread and when the thread terminates all handles become signaled and you can wait any of the handles any number of times until closing the handles. On unix like systems the pthread api is more restrictive: you get a thread handle when you create a (non-detached) thread and you have to wait exactly once and only once for the thread handle. If you don't wait for the thread handle then it causes a leak, if you wait for it multiple times then its an error. Waiting for it once gets the exitcode from the temp object (associated with the thread handle) and also frees this temp object.
Both behaviors can be simulated by a framework but C++11 chose something that is near to the unix philosophy (as implementing that on all platforms is simpler and more performant and usually enough).
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Hi,
i have this Problem in custom CHeaderCtrl control.
My message map look like this:
<br />
BEGIN_MESSAGE_MAP(CHeaderCtrlEx, CHeaderCtrl)<br />
ON_WM_LBUTTONDOWN()<br />
ON_WM_MOUSEMOVE()<br />
ON_WM_LBUTTONDBLCLK()<br />
ON_REGISTERED_MESSAGE(WM_HDN_ENDDRAG, OnHdnEndDrag)<br />
END_MESSAGE_MAP()<br />
Now i want to send a message to this header control but they never received it,
i never had this before so i don't know what cause this?
In a example Project here from codeproject work this "custom header control" very nice, no problems, only in my project?
So what to check, where can be my mistake, what im doing wrong??
Thanks for any help!
regards
bosfan
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Hi,
thans for Answer, yes i have all in my class definition.
It is the same project from:
Here in Codeproject
If i start this example all works fine, but not if i use this
in a new project.
Thanks
bosfan
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bosfan wrote: It is the same project from:
Here in Codeproject
It may be worth talking to the author then.
bosfan wrote: If i start this example all works fine, but not if i use this
in a new project.
Check what you have done that is different, it may help to diagnose the problem.
Veni, vidi, abiit domum
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Hi, i solved, of course, my mistake what else -.-
I have a multiple inheritance of CHeaderCtrl and there was a fault.
big sorry 
regards
bosfan
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I want a example in vc++
1. I want to save image in Sql Server.
2. how to Retrieve image from database
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Just the same as any other data. Save it as VARBINARY[^], or save it in a normal file location and store its path in the database.
Veni, vidi, abiit domum
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try
{
dbImages.Open(CRecordset::dynaset, _T("Select * from Images where 1=2"),
dbImages.appendOnly);
dbImages.AddNew();
CFile fileImage;
CFileStatus fileStatus;
fileImage.Open(fd.GetPathName(), CFile::modeRead);
fileImage.GetStatus(fileStatus);
dbImages.m_BLOBName = fileImage.GetFileTitle();
dbImages.m_BLOBImage.m_dwDataLength = fileStatus.m_size;
HGLOBAL hGlobal = GlobalAlloc(GPTR,fileStatus.m_size);
dbImages.m_BLOBImage.m_hData = GlobalLock(hGlobal);
fileImage.Read(dbImages.m_BLOBImage.m_hData,fileStatus.m_size);
dbImages.SetFieldDirty(&dbImages.m_BLOBImage, TRUE);
dbImages.SetFieldNull(&dbImages.m_BLOBImage,FALSE);
dbImages.Update();
GlobalUnlock(hGlobal);
dbImages.Close();
pList->InsertItem(0,fileImage.GetFileTitle());
}
catch(CException* pE)
{
pE->ReportError();
pE->Delete();
return;
}
>>
>>
>> Here I am getting exception
"String Data Length Mismatch"
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The above code is work in access but not work in sql server.
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Hi guys,
I am not able to create MFC dialog, when the resources are loaded from another language. The dialog gets created if the language is English. I have added a string in the dialg, CLASS "Singleton Application". And in the code, i do a RegisterClass with this class name. Also i am setting the correct AfxSetResourceHandle. If i remove this "CLASS" entry, i am able to create the dialog in other languages. Any pointers would be helpful....
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I didnt do this way...I was just calling DoModal, and while debugging in the MFC code i found out that CreateDialogIndirect is failing...
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DoModal is called on a modal dialog, and CreateDialogIndirect is used to create a modeless one; the two are quite different. Maybe it would be better if you showed exactly what you are doing and where the error occurs.
Veni, vidi, abiit domum
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Dear Sir/Madam
Greeting Of The Day!!!
I am trying to communicate between MFC DLLs. But I got _CrtIsValidHeapPointerUserData() error and I know it is memory heap wastage problem I have done to findoutmemory leak problem from CMemoryState structure with CheckPoint. and #define new DEBUG_NEW also But Now it will give me that error at a time of FreeLibrary or accessing that's function . Plz help me
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You need to provide some more information about where this occurs and what your code is doing. There could be any one of a million reasons for the error.
Veni, vidi, abiit domum
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There are 2 DLL s
First DLL is XMLFILEINTERPRETAION.dll which gives us a Unicode Value and letter id of given each iscii value according to selected script(Devnagari,Gujrati,Gurmukhi,Gujarati,Bengali,Oriya,Tamil,Telugu,Malayalam and Kannada)) from xml file. letterid means English letter which typed by user using Executive keyboard.
Second DLL is DictionaryDataComputation.dll which provides us all dictionary words and we give some suggestion related to given word .And we use first dll for getting suggestions in unicode words and corresponding to english words .if these suggestions are not exist in DLL then these will be display otherwise not .and if user click on these suggestion then these add in my script Dictionary which also build in XML format.
I have used some technologies like DLL, EXE, CArray Template Collection, and MSXML2::DOMDocument for all manipulation (insertion and deletion of nodes) of xml files, Binary Recursion Search Algorithm for sorting and searching in ascending order in xml file.
Whenever I use freeLibrary function then provides this error. if I disable this functionin my code then at first time it does not give any error but this error appears in second time when we are using call DLL function of First DLL.
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It's a reasonable guess that you have a bug in one of these libraries. You could do some debugging for yourself, or talk to the people who provide them.
Veni, vidi, abiit domum
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I am degugging these DLLs so i could find out this reason that is occur due to FreeLibrary and below reason:
Whenever I use freeLibrary function then provides this error. if I disable this functionin my code then at first time it does not give any error but this error appears in second time when we are using call DLL function of First DLL.
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As I said, you have a bug in either your code, or in one of the DLLs, but only you or the developer of the DLLs will be able to find it.
Veni, vidi, abiit domum
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Actually I develop these DLL but I totally disappointed to solveout this problem
Please suggest me some helpfull reason that why is it occured?
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The problem occurs because some code has corrupted the heap at some time, but it is impossible to know where. The only way to solve issues like this is by a lot of debugging and code profiling. There are some free tools for code profiling (Google will find them) which may help you.
Veni, vidi, abiit domum
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start by debugging in the DLL's DllMain functions, especially in when the 'reason for the call' parameter (param #2) is DLL_THREAD_DETACH or DLL_PROCESS_DETACH.
odds are good that one DLL is trying to use something that the other DLL owns, and that that something is being destroyed before the first DLL is done using it.
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As I recall there is a facility to check memory in real time in VC6.
It's called something like AfxCheckMemory (), and there's an option called something like checkalways, that checks your heap after every allocation/free, to pinpoint the memory corruption. (Your problem appears to be more than just a memory leak.)
Your program will run VERY slowly, but it will tell you where the error is. Search your documentation for this version to find the names of the function and option.
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