CODEWITHSUNDEEP
c++visual-c++mfcloadlibrary
coreSOLO
coreSOLO

Reputation: 3619

In MFC APP, if I call "LoadLibraryA" from "InitInstance", it calls "InitInstance" again and again

I have created an MFCApp using VS2008 wizard. Inside my application's "InitInstance()" I'm calling "LoadLibraryA()" method as I need to load a few dll files. But as soon as I call "LoadLibraryA()", it again calls "InitInstance()" of my application and hence it becomes a infinite recursion stuff. Is there something I'm doing wrong?

// CLoader_MFCApp initialization
BOOL CLoader_MFCApp::InitInstance()
{
  INITCOMMONCONTROLSEX InitCtrls;
  InitCtrls.dwSize = sizeof(InitCtrls);
  InitCtrls.dwICC = ICC_WIN95_CLASSES;
  InitCommonControlsEx(&InitCtrls);
  CWinAppEx::InitInstance();
  SetRegistryKey(_T("MyApp"));

  HMODULE hm = LoadLibraryA("./abc/def.dll");
  // after above line InitInstance() gets called again

  // more code
  return FALSE;
}

Call Stack:

MyApp.exe!CLoader_MFCApp::InitInstance()    C++
CORE.dll!InternalDllMain(HINSTANCE__ *, unsigned long, void *)  C++
CORE.dll!__DllMainCRTStartup(void *, unsigned long, void *)     C
CORE.dll!_DllMainCRTStartup(void *, unsigned long, void *)  C
ntdll.dll!_LdrpCallInitRoutine@16()     
ntdll.dll!_LdrpRunInitializeRoutines@4()    
ntdll.dll!_LdrpLoadDll@24()     
ntdll.dll!_LdrLoadDll@16()  
kernel32.dll!_LoadLibraryExW@12()   
kernel32.dll!_LoadLibraryExA@12()   
kernel32.dll!_LoadLibraryA@4()  
MyApp.exe!CLoader_MFCApp::InitInstance()    C++
mfc90.dll!AfxWinMain(HINSTANCE__ *, HINSTANCE__ *, char *, int)     C++
MyApp.exe!__tmainCRTStartup()   C
kernel32.dll!_BaseProcessStart@4()

"Def.dll" is any other dll and completely unrelated from MyApp. In this case, I'm trying to load another dll "CORE.dll"

All I can figure out is that I'm calling LoadLibrary before InitInstance routine is over. Is there any other (overridable) method which is called after InitInstance??? If so, I can try moving LoadLibrary calls to that method...

Upvotes: 3

Views: 1839

Answers (3)

PaulN
PaulN

Reputation: 1

I've just had the same issue, caused by the Configuration type being incorrectly set to exe not dll for the dll to be loaded.

Fix: Project -> Configuration Properties -> General -> Configuration Type = Dynamic Library (.dll) (was incorrectly set to Application (.exe))

Upvotes: 0

Ben
Ben

Reputation: 26

Yes, you are doing something wrong. You are in mfc90.dll's DllMain and it is not safe to call LoadLibrary from DllMain, says so right here:

http://msdn.microsoft.com/en-us/library/ms684175%28v=vs.85%29.aspx

Upvotes: 1

Mordachai
Mordachai

Reputation: 9662

This is more of a workaround than a true solution (i.e. I don't know the rules for LoadLibrary in MFC, as I've never read anything to say you can't, nor do I happen to use this technique in our MFC code).

However, Generally speaking, if windows coughs up a hairball due to order of operations, I just move the calls out to another message handler. You can even post a thread message to your application, and write a handler for that message.

Something like:

// in InitInstance - post a message to our main thread to handle after init instance...
PostMessage(NULL, WM_PostInit);

// in your message table
ON_THREAD_MESSAGE(WM_PostInit, OnPostInit)

// in your app
void MyApp::OnPostInit(WPARAM,LPARAM) // both args unused
{
  // try load library now...!
}

NOTE: The above is "brain code" - untested. Details undoubtedly need to be massaged for full compilability.

References: http://msdn.microsoft.com/en-us/library/ms644944%28v=VS.85%29.aspx

Upvotes: 1

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