Possible Duplicate:
pinvokestackimbalance — how can I fix this or turn it off?
I need to access a c++ dll library (I don't have the source code) from c# code.
for example the following functions:
UINT32 myfunc1()
UINT32 myfunc2(IN char * var1)
UINT32 myfunc3(IN char * var1, OUT UINT32 * var2)
For myfunc1 I have no problems when I use the following code:
[DllImport("mydll.dll")]
public static extern int myfunc1();
On the other hand I was unable to use myfunc2 and myfunc3. For myfunc2 I tried the following: (and many others desperately)
[DllImport("mydll.dll")]
public static extern int myfunc2(string var1);
[DllImport("mydll.dll")]
public static extern int myfunc2([MarshalAs(UnmanagedType.LPStr)] string var1);
[DllImport("mydll.dll")]
public static extern int myfunc2(char[] var1);
But all of them gave the following error:
"Managed Debugging Assistant 'PInvokeStackImbalance' has detected a problem in 'C:\Users\....\myproject\bin\Debug\myproj.vshost.exe'.
Additional Information: A call to PInvoke function 'myproject!myproject.mydll::myfunc2'
has unbalanced the stack. This is likely because the managed PInvoke signature does not match the unmanaged target signature. Check that the calling convention and parameters of the PInvoke signature match the target unmanaged signature."
Please, guide on what I should do.
You can open the command prompt by going to the Windows Start menu or by holding Windows Key+R and typing "cmd" in the prompt that appears on screen. Open the folder with the DLL file. Once you find the folder, hold the Shift key and right-click the folder to open the command prompt directly in that folder.
Yes, it will work. Just make sure you reference the library in your c++ library and link them together. In some cases, this is not possible, e.g. if there is a considerable existing codebase written in C, that needs to be extended with new functionality (which is to be written in C++).
DLLs are executables. A statically linked app has its own copy of the library. A DLL can be used simultaneously by many apps. Static-link libraries can have code and data.
Your C++ functions use the cdecl
calling convention, but the default calling convention for DllImport
is stdcall
. This calling convention mismatch is the most common cause of the stack imbalanced MDA error.
You fix the problem by making the calling conventions match. The easiest way to do that is to change the C# code to specify cdecl
like this:
[DllImport("mydll.dll", CallingConvention=CallingConvention.Cdecl)]
public static extern int myfunc2(string var1);
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