从 C# 程序启动的 MFC dll(封装在 C++/CLI 中)中的访问冲突
我已经为 mfc dll (C++) 编写了一个托管 C++/CLI 包装器,并且在第二次调用 dll 后出现了一些访问冲突!
ReaderCommunication 和 CSmartMaskCmds 构造中的包装器
// in .h
typedef CKeyManagerServerApp* (*KeyManagerInstance)(CCommonUtils *);
ManagedKeyInterface::ManagedKeyInterface()
{
HINSTANCE m_keyManagerLib = LoadLibrary("pathToDll");
KeyManagerInstance _createInstance = (KeyManagerInstance)GetProcAddress(m_keyManagerLib, "GetInstance");
// get native reader interface from managed reader interface
CCommonUtils *nativeReaderInterface = static_cast<CCommonUtils*>(readerInterface->nativeReaderInterface.ToPointer());
CKeyManagerServerApp *m_keyManagerApp = (_createInstance)(nativeReaderInterface );
}
ManagedKeyInterface::~ManagedKeyInterface()
{
try
{
DestroyKeyManagerInstance _destroyInstance = (DestroyKeyManagerInstance)GetProcAddress(m_keyManagerLib, "DestroyInstance");
(_destroyInstance)(m_keyManagerApp);
FreeLibrary(m_keyManagerLib);
}
catch(System::Exception ^e)
{
FreeLibrary(m_keyManagerLib);
}
}
本机 MFC 类
extern "C" _declspec(dllexport) CKeyManagerServerApp* GetInstance(CCommonUtils *readerInterface)
{
AFX_MANAGE_STATE(AfxGetStaticModuleState());
return new CKeyManagerServerApp(readerInterface);
}
extern "C" _declspec(dllexport) void DestroyInstance(CKeyManagerServerApp *ptr)
{
AFX_MANAGE_STATE(AfxGetStaticModuleState());
delete ptr;
}
// constructor
CKeyManagerServerApp::CKeyManagerServerApp(CCommonUtils *readerInterface)
{
m_log = new Logging(loggingFilePath); // <--- ERROR at second call
// reader interface object for communication
m_readerComm = new ReaderCommunication(readerInterface, m_log);
m_smartmaskcmds = new CSmartMaskCmds(m_readerComm, m_log);
readerInterface = NULL;
}
// destructor
CKeyManagerServerApp::~CKeyManagerServerApp()
{
// destruct objects
delete m_smartmaskcmds;
delete m_readerComm;
delete m_log;
}
。该对象只会被分配!
在 C# 程序的第一次运行时(加载了带有添加引用的包装器)一切正常,但是当我再次启动它时,我得到:
TestKeyManagerApp.exe 中 0x76f85b57 处的第一次机会异常:0xC0000005:访问冲突读取位置 0xdddddddd。 TestKeyManagerApp.exe 中 0x75169617 处的第一次机会异常:Microsoft C++ 异常:内存位置 0x0024e820 处的 CMemoryException..
当我调用 m_log = new Logging(loggingFilePath) 时,
析构函数似乎无法正常工作!?
有什么想法吗????
谢谢你!
I have written an managed C++/CLI wrapper for mfc dll (C++) and have some access violations after second call of dll!
Wrapper
// in .h
typedef CKeyManagerServerApp* (*KeyManagerInstance)(CCommonUtils *);
ManagedKeyInterface::ManagedKeyInterface()
{
HINSTANCE m_keyManagerLib = LoadLibrary("pathToDll");
KeyManagerInstance _createInstance = (KeyManagerInstance)GetProcAddress(m_keyManagerLib, "GetInstance");
// get native reader interface from managed reader interface
CCommonUtils *nativeReaderInterface = static_cast<CCommonUtils*>(readerInterface->nativeReaderInterface.ToPointer());
CKeyManagerServerApp *m_keyManagerApp = (_createInstance)(nativeReaderInterface );
}
ManagedKeyInterface::~ManagedKeyInterface()
{
try
{
DestroyKeyManagerInstance _destroyInstance = (DestroyKeyManagerInstance)GetProcAddress(m_keyManagerLib, "DestroyInstance");
(_destroyInstance)(m_keyManagerApp);
FreeLibrary(m_keyManagerLib);
}
catch(System::Exception ^e)
{
FreeLibrary(m_keyManagerLib);
}
}
NATIVE MFC CLASS
extern "C" _declspec(dllexport) CKeyManagerServerApp* GetInstance(CCommonUtils *readerInterface)
{
AFX_MANAGE_STATE(AfxGetStaticModuleState());
return new CKeyManagerServerApp(readerInterface);
}
extern "C" _declspec(dllexport) void DestroyInstance(CKeyManagerServerApp *ptr)
{
AFX_MANAGE_STATE(AfxGetStaticModuleState());
delete ptr;
}
// constructor
CKeyManagerServerApp::CKeyManagerServerApp(CCommonUtils *readerInterface)
{
m_log = new Logging(loggingFilePath); // <--- ERROR at second call
// reader interface object for communication
m_readerComm = new ReaderCommunication(readerInterface, m_log);
m_smartmaskcmds = new CSmartMaskCmds(m_readerComm, m_log);
readerInterface = NULL;
}
// destructor
CKeyManagerServerApp::~CKeyManagerServerApp()
{
// destruct objects
delete m_smartmaskcmds;
delete m_readerComm;
delete m_log;
}
in ReaderCommunication and CSmartMaskCmds constr. the object will only assigned!
At first runtime of the C# program (loaded the wrapper with add reference) everything works fine, but when I start it again I get:
First-chance exception at 0x76f85b57 in TestKeyManagerApp.exe: 0xC0000005: Access violation reading location 0xdddddddd.
First-chance exception at 0x75169617 in TestKeyManagerApp.exe: Microsoft C++ exception: CMemoryException at memory location 0x0024e820..
when I call m_log = new Logging(loggingFilePath)
It seems the destructor does not work right!?
Any ideas!!??
Thank you!
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当您看到值
0xdddddddd
时,这意味着 某些指针被删除(VC 将在调试版本上设置该值以帮助您识别这些情况)。您没有告诉我们什么是loggingFilePath
以及Logging
是如何实现的,但我猜测loggingFilePath
在某个时候被删除,并且>Logging
尝试访问其值或构造函数(或初始化列表)中的虚拟函数。这也可以解释析构函数中的崩溃 - 您正在删除
m_log
,它可能包含从loggingFilePath
获得的非法指针。当您尝试再次使用它时,您会遇到同样的崩溃。When you see the value
0xdddddddd
, it means that some pointer was deleted (VC will set that value on debug builds to help you recognize these cases). You don't tell us what'sloggingFilePath
and howLogging
is implemented, but my guess is thatloggingFilePath
is deleted at some point, andLogging
tries to access its value or a virtual function in the constructor (or initialization list).This could also explain the crash in the destructor - you're deleting
m_log
, which probably holds an illegal pointer it got fromloggingFilePath
. When you try to use it again, you get the same crash.幕后发生了什么?找出它到底崩溃的地方。如果您使用 C#,请启用非托管调试。我猜问题出在
Logging
构造函数下。What's happening behind the scenes? Find out where exactly it crashes. Enable unmanaged debugging if you are using C#. I guess the problem is under
Logging
constructor.