DLL_THREAD_ATTACH & _DETACH being called repeatedly in DLL
in [Win32 API]
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From: Robert Oschler on 9 May 2005 23:11 I have a MSVC 6.x application that is used by a Delphi 6 application. The MSVC DLL is being loaded dynamically using LoadLibrary(). For debugging purposes, I put code in the MSVC DLL that counts each occurrence of DLL_THREAD_ATTACH & DLL_THREAD_DETACH using a static integer counter. I am seeing the following strange behavior when I run the Delphi app as the debugger target for the MSVC DLL project, in the IDE: DLL_THREAD_ATTACH is called many times as the application is starting up. DLL_THREAD_ATTACH & DLL_THREAD_DETACH seems to be called each time I open and close the wave device. This is really strange because the code that opens and closes the wave devices is *in the Delphi app* and not the MSVC DLL and should not have an effect on the MSVC DLL. In all cases the parent process shown by the MSVC call stack (OutputDebugString results) is DllMain, then _DLLMainCrtStartup, then a few NTDLL calls above that. I have included the debug monitor output below. A couple of notes about the output: - Any message that is preceded by '***' are coming from the Delphi app. - The intializeEngine, beginUtterance, endUtterance, and any message preceded by "VServer1" are coming from my MSVC DLL. - All other messages are either DLL "Loaded" messages or messages from other DLL's that my app uses. This is really strange. What could be causing this and how can I fix it? Thanks Robert ---------------- DEBUG MONITOR OUTPUT ------------- Loaded 'C:\Projects_Delphi_OSDN\MusicVox\voxtail.exe', no matching symbolic information found. Loaded 'C:\WINNT\system32\ntdll.dll', no matching symbolic information found. Loaded 'C:\WINNT\system32\KERNEL32.DLL', no matching symbolic information found. Loaded 'C:\WINNT\system32\USER32.DLL', no matching symbolic information found. Loaded 'C:\WINNT\system32\GDI32.DLL', no matching symbolic information found. Loaded 'C:\WINNT\system32\ADVAPI32.DLL', no matching symbolic information found. Loaded 'C:\WINNT\system32\rpcrt4.dll', no matching symbolic information found. Loaded 'C:\WINNT\system32\OLEAUT32.DLL', no matching symbolic information found. Loaded 'C:\WINNT\system32\OLE32.DLL', no matching symbolic information found. Loaded 'C:\WINNT\system32\version.dll', no matching symbolic information found. Loaded 'C:\WINNT\system32\lz32.dll', no matching symbolic information found. Loaded 'C:\WINNT\system32\comctl32.dll', no matching symbolic information found. Loaded 'C:\WINNT\system32\WINSPOOL.DRV', no matching symbolic information found. Loaded 'C:\WINNT\system32\mpr.dll', no matching symbolic information found. Loaded 'C:\WINNT\system32\SHELL32.DLL', no matching symbolic information found. Loaded 'C:\WINNT\system32\SHLWAPI.DLL', no matching symbolic information found. Loaded 'C:\WINNT\system32\msvcrt.dll', no matching symbolic information found. Loaded 'C:\WINNT\system32\COMDLG32.DLL', no matching symbolic information found. Loaded 'C:\WINNT\system32\wsock32.dll', no matching symbolic information found. Loaded 'C:\WINNT\system32\ws2_32.dll', no matching symbolic information found. Loaded 'C:\WINNT\system32\ws2help.dll', no matching symbolic information found. Loaded 'C:\WINNT\system32\winmm.dll', no matching symbolic information found. Preloaded symbols may not match 'C:\Projects_Delphi_OSDN\MusicVox\sphinx\vserver1.dll'. Loaded symbols for 'C:\WINNT\system32\MSVCRTD.DLL' Loaded 'C:\WINNT\system32\serwvdrv.dll', no matching symbolic information found. Loaded 'C:\WINNT\system32\umdmxfrm.dll', no matching symbolic information found. Loaded 'C:\WINNT\system32\ctwdm32.dll', no matching symbolic information found. LoadEnableFound one versionOpenCloseDisableFreeVServer1 DLL_PROCESS_ATTACH called(1). Loaded 'C:\Program Files\ScanSoft\OmniPagePro11.0\ophook32.dll', no matching symbolic information found. Loaded 'C:\WINNT\system32\OLEPRO32.DLL', no matching symbolic information found. Loaded 'C:\WINNT\system32\clbcatq.dll', no matching symbolic information found. VServer1 DLL_THREAD_ATTACH called(1). Loaded 'C:\WINNT\system32\SHDOCVW.DLL', no matching symbolic information found. Loaded 'C:\WINNT\system32\WININET.DLL', no matching symbolic information found. Loaded 'C:\WINNT\system32\CRYPT32.DLL', no matching symbolic information found. Loaded 'C:\WINNT\system32\msasn1.dll', no matching symbolic information found. VServer1 DLL_THREAD_ATTACH called(2). Loaded 'C:\WINNT\system32\riched32.dll', no matching symbolic information found. Loaded 'C:\WINNT\system32\riched20.dll', no matching symbolic information found. Loaded 'C:\WINNT\system32\uuirtdrv.dll', no matching symbolic information found. UUIRTOpen: ThreadID = 000006b4 Creating New Global Set! Loaded 'C:\WINNT\system32\FTD2XX.dll', no matching symbolic information found. Loaded 'C:\WINNT\system32\SETUPAPI.DLL', no matching symbolic information found. Loaded 'C:\WINNT\system32\USERENV.DLL', no matching symbolic information found. VServer1 DLL_THREAD_ATTACH called(3). Starting IRThread VServer1 DLL_THREAD_ATTACH called(4). Now taking over dispatch ownership! VServer1 DLL_THREAD_ATTACH called(5). *** ============================================================================ Dispatch: TransmitIR PAUSE RESUME *** doStopCommand Executed. *** WM_PLAY_HAS_ENDED message sent(2). *** (SphinxLink) Calling Load Library. *** (SphinxLink) Assigning function pointers. initializeEngine() called. Loaded 'C:\WINNT\system32\shdoclc.dll', no matching symbolic information found. Loaded 'C:\WINNT\system32\URLMON.DLL', no matching symbolic information found. Loaded 'C:\WINNT\system32\mlang.dll', no matching symbolic information found. VServer1 DLL_THREAD_ATTACH called(6). Loaded 'C:\WINNT\system32\msafd.dll', no matching symbolic information found. Loaded 'C:\WINNT\system32\wshtcpip.dll', no matching symbolic information found. VServer1 DLL_THREAD_ATTACH called(7). Loaded 'C:\WINNT\system32\RASAPI32.DLL', no matching symbolic information found. Loaded 'C:\WINNT\system32\RASMAN.DLL', no matching symbolic information found. Loaded 'C:\WINNT\system32\TAPI32.DLL', no matching symbolic information foun d. Loaded 'C:\WINNT\system32\rtutils.dll', no matching symbolic information found. VServer1 DLL_THREAD_ATTACH called(8). Loaded 'C:\WINNT\system32\sensapi.dll', no matching symbolic information found. Loaded 'C:\WINNT\system32\NETAPI32.DLL', no matching symbolic information found. Loaded 'C:\WINNT\system32\secur32.dll', no matching symbolic information found. Loaded 'C:\WINNT\system32\ntdsapi.dll', no matching symbolic information found. Loaded 'C:\WINNT\system32\dnsapi.dll', no matching symbolic information found. Loaded 'C:\WINNT\system32\WLDAP32.DLL', no matching symbolic information found. Loaded 'C:\WINNT\system32\netrap.dll', no matching symbolic information found. Loaded 'C:\WINNT\system32\samlib.dll', no matching symbolic information found. Loaded 'C:\WINNT\system32\RSABASE.DLL', no matching symbolic information found. VServer1 DLL_THREAD_ATTACH called(9). Loaded 'C:\WINNT\system32\RNR20.DLL', no matching symbolic information found. Loaded 'C:\WINNT\system32\IPHLPAPI.DLL', no matching symbolic information found. Loaded 'C:\WINNT\system32\icmp.dll', no matching symbolic information found. Loaded 'C:\WINNT\system32\mprapi.dll', no matching symbolic information found. Loaded 'C:\WINNT\system32\activeds.dll', no matching symbolic information found. Loaded 'C:\WINNT\system32\adsldpc.dll', no matching symbolic information found. Loaded 'C:\WINNT\system32\DHCPCSVC.DLL', no matching symbolic information found. Loaded 'C:\WINNT\system32\winrnr.dll', no matching symbolic information found. Loaded 'C:\WINNT\system32\rasadhlp.dll', no matching symbolic information found. VServer1 DLL_THREAD_ATTACH called(10). Loaded 'C:\WINNT\system32\MSHTML.DLL', no matching symbolic information found. VServer1 DLL_THREAD_ATTACH called(11). VServer1 DLL_THREAD_ATTACH called(12). Loaded 'C:\WINNT\system32\msls31.dll', no matching symbolic information found. Loaded 'C:\WINNT\system32\imm32.dll', no matching symbolic information found. VServer1 DLL_THREAD_ATTACH called(13). Loaded 'C:\WINNT\system32\cscui.dll', no matching symbolic information found. Loaded 'C:\WINNT\system32\cscdll.dll', no matching symbolic information found. beginUtterance() called. Loaded 'C:\WINNT\system32\wdmaud.drv', no matching symbolic information found. Loaded 'C:\WINNT\system32\wdmaud.drv', no matching symbolic information found. Loaded 'C:\WINNT\system32\wdmaud.drv', no matching symbolic information found. Loaded 'C:\WINNT\system32\wdmaud.drv', no matching symbolic information found. Loaded 'C:\WINNT\system32\wdmaud.drv', no matching symbolic information found. Loaded 'C:\WINNT\system32\wdmaud.drv', no matching symbolic information found. Loaded 'C:\WINNT\system32\wdmaud.drv', no matching symbolic information found. Loaded 'C:\WINNT\system32\wdmaud.drv', no matching symbolic information found. Loaded 'C:\WINNT\system32\wdmaud.drv', no matching symbolic information found. VServer1 DLL_THREAD_ATTACH called(14). Loaded 'C:\WINNT\system32\msacm32.drv', no matching symbolic information found. Loaded 'C:\WINNT\system32\msacm32.dll', no matching symbolic information found. VServer1 DLL_THREAD_ATTACH called(15). *** Wave Device Opened. endUtterance() called. beginUtterance() called. VServer1 DLL_THREAD_DETACH called(1). The thread 0x900 has exited with code 0 (0x0). *** Wave Device Closed. endUtterance() called. VServer1 DLL_THREAD_ATTACH called(16). *** Wave Device Opened. VServer1 DLL_THREAD_DETACH called(2). The thread 0x4B0 has exited with code 0 (0x0). First-chance exception in voxtail.exe (KERNEL32.DLL): 0x0EEDFADE: (no name). *** Wave Device Closed.
From: Alex Blekhman on 10 May 2005 04:04 Robert Oschler wrote: > I am seeing the following strange behavior when I run the > Delphi app as the debugger target for the MSVC DLL > project, in the IDE: > > DLL_THREAD_ATTACH is called many times as the application > is starting up. > > DLL_THREAD_ATTACH & DLL_THREAD_DETACH seems to be called > each time I open and close the wave device. This is > really strange because the code that opens and closes the > wave devices is *in the Delphi app* and not the MSVC DLL > and should not have an effect on the MSVC DLL. That's not strange at all. When new thread is created or existing thread exits, then *all* loaded DLLs are notified with DLL_THREAD_ATTACH/DETACH.
From: Robert Oschler on 10 May 2005 12:08 "Alex Blekhman" <tkfx^N05P4M^@yahoo.com> wrote in message news:3eb88aF24tchU1(a)individual.net... > That's not strange at all. When new thread is created or > existing thread exits, then *all* loaded DLLs are notified > with DLL_THREAD_ATTACH/DETACH. > > Ok, that makes sense. I thought a DLL_THREAD_ATTACH/DETACH message meant *my DLL's* thread was being attached or detached. What use is it to know when a new thread is created that doesn't really affect your DLL? I'm guessing the new thread that is being repeatedly recreated is the Wave device thread, created by the Windows multimedia DLL when I open and close the wave device. I'm still having trouble getting my DLL to fully unload when I call FreeLibrary(). I'm guessing someone or something is increasing the DLL reference count beyond 1, but I still haven't figured out what. I was hoping that this DLL_THREAD_ATTACH/DETACH behavior was related, but if I understand you correctly, it's not. Thanks, Robert
From: Alex Blekhman on 10 May 2005 12:32 Robert Oschler wrote: > Ok, that makes sense. I thought a > DLL_THREAD_ATTACH/DETACH message meant *my DLL's* thread > was being attached or detached. Actually, DLL doesn't have any thread. It's just loaded into procerss address space. Then any thread can run code from the DLL. > What use is it to know when a new thread is created that > doesn't really affect your DLL? Some libraries want to store thread specific data, so calls from one thread won't affect state of library for other threads. These libraries usually use Thread Local Storage (TLS) functions in DLL_THREAD_ATTACH/DETACH case. For example, CRT implementation of strtok() function relies on TLS, so you can call it from different threads. > I'm still having trouble getting my DLL to fully unload > when I call FreeLibrary(). Do you do something wicked on DLL_PROCESS_DETACH notification?
From: Tim Kannel on 11 May 2005 00:07
> That's not strange at all. When new thread is created or > existing thread exits, then *all* loaded DLLs are notified > with DLL_THREAD_ATTACH/DETACH. .... except DLLS referenced in calls to DisableThreadLibraryCalls() -- Tim Kannel TCAP - Captures console I/O to a file (DOS,Win9x) http://www.simtel.net/pub/pd/11141.shtml |