Anyone know how i fix this error?
ERROR:
A call to PInvoke function 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.
I am using P/Invoke to call a native code from a managed code. Native code is being imported via dynamic link libraries.
Steps are
Locating .dll containing these function.
Loading .dll into memory
Locating the address of function in memory
Transforming this memory representation of object to a data format (marshalling)
DLL has a function with declaration
long __stdcall Connect (long,long,long,long,long,long,long,long);`
In my application i created a delegate
[UnmanagedFunctionPointer(CallingConvention.StdCall)]
private delegate long delConnect(long a, long b, long c, long d, long e, long f, long g, long h);`
Then i created a class for loading dll and locating address of function in memory
`static class NativeMethods
{
[DllImport("kernel32.dll")]
public static extern IntPtr LoadLibrary(string dllToLoad);
[DllImport("kernel32.dll")]
public static extern IntPtr GetProcAddress(IntPtr hModule, string procedureName);
[DllImport("kernel32.dll")]
public static extern bool FreeLibrary(IntPtr hModule);
}`
Now when i am trying to use the function then i am getting error
IntPtr pDll = NativeMethods.LoadLibrary("serial.dll");
IntPtr pAddressOfFunctionToCall = NativeMethods.GetProcAddress(pDll, "_Connect#32");
delConnect connect = (delConnect)Marshal.GetDelegateForFunctionPointer(pAddressOfFunctionToCall,typeof(delConnect));
long check = connect(1, 0, 12, 9600, 0, 0, 8, 0);
bool result = NativeMethods.FreeLibrary(pDll);`
I have used "_Connect#32" instead of "Connect" in function name parameters of GetProcAddress method, because of name mangling.
When i am debugging i get this error at line containing statement
long check = connect(1, 0, 12, 9600, 0, 0, 8, 0);
The C/C++ long is 32 bit in Windows, so an int in .net. Try changing it (on Unix it's more like an IntPtr)
[UnmanagedFunctionPointer(CallingConvention.StdCall)]
private delegate int delConnect(int a, int b, int c, int d, int e, int f, int g, int h);
And perhaps instead of StdCall try Cdecl:
[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
For the DllImport of Windows API you should use
[DllImport("kernel32.dll", CharSet=CharSet.Auto)]
So that if possible .NET uses the Unicode variant, and not the Ansi variant.
Is there a reason you're using LoadLibrary() rather than just PInvoking directly?
What happens if you try this instead:
[DllImport("serial.dll", EntryPoint = "_Connect#32", CallingConvention = CallingConvention.StdCall)]
static extern int DelConnect(int a, int b, int c, int d, int e, int f, int g, int h);
(Note C# int == C++ long, normally)
Related
I'm trying to PInvoke the following function from GitHub's fork of CMark
char *cmark_markdown_to_html(const char *text, size_t len, int options)
and here's my PInvoke signature:
[DllImport("cmark.dll")]
public static extern IntPtr cmark_markdown_to_html(
[In()] [MarshalAs(UnmanagedType.LPStr)] string text,
[MarshalAs(UnmanagedType.SysUInt)] uint len,
[MarshalAs(UnmanagedType.SysInt)] int options);
I call it as follows:
var retValue = cmark_markdown_to_html(markdown, 0, 0);
However, it throws a Marshaling exception the with the message:
Cannot marshal 'parameter #2':
Invalid managed/unmanaged type combination
(Int32/UInt32 must be paired with I4, U4, or Error).
OK, so I change the signature to:
[DllImport("cmark.dll")]
public static extern IntPtr cmark_markdown_to_html(
[In, MarshalAs(UnmanagedType.LPStr)] string text,
[MarshalAs(UnmanagedType.U4)] uint len,
[MarshalAs(UnmanagedType.I4)] int options);
Now it throws a PInvokeStackImbalance error
The name '$exception' does not exist in the current context
Native stuff is a mystery to me. Can someone help?
Stack imbalance
The reason for stack imbalance is described in Why are Cdecl calls often mismatched in the "standard" P/Invoke Convention?.
Basically you need to specify proper calling convention in the DllImport that will probably be cdecl:
[DllImport("cmark.dll", CallingConvention = CallingConvention.Cdecl)]
Marshalling size_t
That one is discussed in what is equal to the c++ size_t in c# .
Assuming that CMark will always be native (32 bit on x86, 64 bit on x64), you should use (U)IntPtr.
If it is always 32 bit, then Int32 should be used.
PInvokeStackImbalance
Presumably CMark is using the default calling convention. The default calling convention for C code is "Cdecl", while the default used for P/invoke calls is "StdCall". The calling convention specifies how the arguments and return value are placed on the call stack. A mismatch between the used calling convention causes the stack to become imbalanced.
You can specify the calling convention to use from C# code in the DllImport attribute.
[DllImport("cmark.dll", CallingConvention = CallingConvention.Cdecl)]
public static extern IntPtr cmark_markdown_to_html(
[In, MarshalAs(UnmanagedType.LPStr)] string text,
[MarshalAs(UnmanagedType.U4)] uint len,
[MarshalAs(UnmanagedType.I4)] int options);
Marshalling
In case you want your code to be compatible with architectures other than 32-bit, you would want to marshall size_t with UIntPtr. (Read #Eugene Podskal answer)
[DllImport("cmark.dll", CallingConvention = CallingConvention.Cdecl)]
public static extern IntPtr cmark_markdown_to_html(
[In, MarshalAs(UnmanagedType.LPStr)] string text,
[MarshalAs(UnmanagedType.U4)] UIntPtr len,
[MarshalAs(UnmanagedType.I4)] int options);
Then you can call the method like so
var retValue = cmark_markdown_to_html(markdown, UIntPtr.Zero, 0);
I am trying to wrap the bass.dll. Simple functions not too Advanced. Dont want to get that deep. However i am facing problems.
This is how i import the functions:
[DllImport("bass.dll")]
public static extern long BASS_Start();
[DllImport("bass.dll")]
public static extern bool BASS_Init(int device, uint freq, uint flag, IntPtr hParent, uint GUID);
[DllImport("bass.dll")]
public static extern long BASS_StreamCreateFile(bool mem, string file, uint offset, uint length, uint flags);
[DllImport("bass.dll")]
public static extern long BASS_ChannelPlay(long handle, long restart);
[DllImport("user32.dll")]
but when i call them, it doesn't work. I get the PInvokeStackImbalance error.
Managed Debugging Assistant 'PInvokeStackImbalance' has detected a problem in 'C:\Users\test\Desktop\testv.1.0.0\update\updated\test\test\bin\Release\test.exe'.
Additional information: A call to PInvoke function 'test!test.Main::BASS_StreamCreateFile' 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.
This is the way i am calling them.
BASS_Start();
BASS_Init(-1, 44100, 0, IntPtr.Zero, 0);
long handle = BASS_StreamCreateFile(false, #"C:\Users\test\Desktop\James Morrison.mp3", 0, 0, 0);
//MessageBox.Show("Playing: " + handle.ToString());
BASS_ChannelPlay(handle, 1);
Thread.Sleep(10000);
I tried desactivating PInvokeStackImbalance but it didn't change anything. Just stopped occuring PInvokeStackImbalance. Hence it doesn't work.
Any ideas?
Thank you in advance.
P.S. please don't give me advices to use Bass.Net.
Your translations are very badly wrong. Every single one contains mistakes, I am afraid to say.
They should be:
[DllImport("bass.dll")]
public static extern bool BASS_Start();
[DllImport("bass.dll")]
public static extern bool BASS_Init(int device, uint freq, uint flag,
IntPtr hParent, ref GUID guid);
[DllImport("bass.dll")]
public static extern uint BASS_StreamCreateFile(bool mem, string file, ulong offset,
ulong length, uint flags);
[DllImport("bass.dll")]
public static extern bool BASS_ChannelPlay(uint handle, bool restart);
I suggest that you make sure you have the BASS C++ header file at hand, and also that you revise your knowledge of what the basic types are for C++ and C#.
I'm adding new disk device to system from my C# code, so I want to call
[System.Runtime.InteropServices.DllImport("Shell32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
public extern static void SHChangeNotify(long wEventId, uint uFlags, IntPtr dwItem1, IntPtr dwItem2);
like below
MyWin32Functions.SHChangeNotify(0x00000100/*ADDRIVE*/, 0x0005/*PATHW*/, driveLetter, IntPtr.Zero);
dwItem1 is void* and we should pass a wchar_t* (pointing to null terminated string) containing drive root in this case; so driveLetter above is
string letter = "Z:\\";
byte[] data = Encoding.Default.GetBytes(letter);
byte[] zdata = new byte[data.Length + 1];
data.CopyTo(zdata, 0);
IntPtr p = System.Runtime.InteropServices.Marshal.AllocHGlobal(zdata.Length);
System.Runtime.InteropServices.Marshal.Copy(zdata, 0, p, zdata.Length);
(my code almost same as code in similiar case: How to call SHChangeNotify from C# without error 14007
but I get System.AccessViolationException)
Any suggestions what am I doing wrong?
The first parameter in your interop signature should be an int, not a long. Though the Win32 function is declared as LONG, a LONG in Win32 is 32-bit.
[System.Runtime.InteropServices.DllImport("Shell32.dll")]
public extern static void SHChangeNotify(int wEventId, uint uFlags, IntPtr dwItem1, IntPtr dwItem2);
This MSDN article shows the common mapping between Win32 types an .NET types for Platform Invoke.
I think I have basically understood how to write c# delegates for callbacks, but this one is confusing me.
The c++ definition is as follows:
typedef int (__stdcall* Callback)(
long lCode,
long lParamSize,
void* pParam
);
and my c# approach would be:
unsafe delegate int CallbackDelegate (int lCode, int lParamSize, IntPtr pParam);
Although this seems to be incorrect, because I get a PInvokeStackInbalance error, which means my definition of the delegate is wrong.
The rest of the parameters of the function are strings or ints, which means they cannot cause the error, and if I just pass a IntPtr.Zero instead of the delegate (which would mean I'm pointing to a non-existent callback function) I get an AccessViolation error, which makes sense aswell.
What am I doing wrong?
EDIT:
The full c++ function is:
int
__stdcall
_Initialize (
const char* FileName,
Callback cbFunction,
int Code,
const char* Name,
unsigned int Option,
unsigned int Option2
);
My c# version is:
[DllImport("MyDll.dll", CallingConvention = CallingConvention.StdCall)]
public static extern int _Initialize (string FileName, CallbackDelegate cbFunction, int Code, string Name, uint Options, uint Options2);
The function is (for testing) just called inside of the main routine of a console application:
static void Main(string[] args)
{
CallbackDelegate del = new CallbackDelegate(onCallback);
Console.Write(_Initialize("SomeFile.dat", del, 1000, "", 0, 4));
Console.Read();
}
where onCallback is this:
static int onCallback(int lCode, int lParamSize, IntPtr pParam)
{
return 0;
}
I get the PInvokeStackInbalance error on the line where I call _Initialize, if I pass a IntPtr.Zero instead of the delegate, and change the definition of the function to IntPtr instead of CallbackDelegate then I get a AccessViolationException.
I added your code to my current project where I'm doing a lot of C#/C++ interop in VS2012. And while I hate to use the "it worked on my machine", it worked fine for me. The code as I ran it is listed out below just to illustrate that I didn't make and fundamental changes.
My suggestion is that you build a new native dll with a stub function for _Initialize such as below and see if it works when you can control both sides of the interface. If that works but the real dll doesn't, it comes down to either compiler settings on the native side or their is a bug on the native side and it is stomping on the stack.
extern "C" {
typedef int (__stdcall* Callback)(long lCode,long lParamSize,void* pParam );
TRADITIONALDLL_API int __stdcall _Initialize (const char* FileName,Callback cbFunction, int Code,
const char* Name,unsigned int Option,unsigned int Option2)
{
cbFunction(0, 0, nullptr);
return 0;
}
}
On the C# side, I added the declarations to my interface class:
public delegate int CallbackDelegate(int lCode, int lParamSize, IntPtr pParam);
[DllImport("XXX.dll", CallingConvention = CallingConvention.StdCall)]
public static extern int _Initialize(string FileName, CallbackDelegate cbFunction, int Code, string Name, uint Options, uint Options2);
And then in my main:
private int onCallback(int lCode, int lParamSize, IntPtr pParam)
{
return 0;
}
XXXInterface.CallbackDelegate del = new XXXInterface.CallbackDelegate(onCallback);
Console.Write(XXXInterface._Initialize("SomeFile.dat", del, 1000, "", 0, 4));
A .NET long is 64bits. A C++ long may be just 32bits. Check with the C++ compiler which compiled that definition as to what size it's longs are.
[UnmanagedFunctionPointerAttribute(CallingConvention.StdCall)]
unsafe delegate int CallbackDelegate (int lCode, int lParamSize, IntPtr pParam);
If .NET assumes cdecl instead of stdcall, your stack will most assuredly be hosed.
I'm having trouble interoperating with a DLL written in C. I'm not sure what type of param to put in place of void*
This is how the API of given DLL looks like:
POSNET_API POSNET_STATUS __stdcall POS_SetDeviceParam ( POSNET_HANDLE hDevice,
unsigned long paramCode,
void * paramValue
)
this is how I was trying to import it in C#:
[DllImport(EXT_DLL)]
private static extern int POS_SetDeviceParam(IntPtr hDevice, int POSNET_DEV_PARAM_IP, *type* paramValue);
in place of type I was putting:
[MarshalAs(UnmanagedType.LPStr)] string and other L*Str
[MarshalAs(UnmanagedType.LPArray)] char[] and other type of arrays including of type byte
IntPtr which where AllocHGlobal, GCHandle.Alloc allocated before
even preceeding the method with unsafe and type = void*, combining above alloc aso.
raw type: string, char[]...
I ran out of possibilities by myself.
paramValue should have a value of an IP in following format: "192.168.1.1" - this is how it looks like in a C demo:
string ip="10.33.44.6";
POS_SetDeviceParam(hDevice,POSNET_DEV_PARAM_IP,(void*)ip.c_str());
In C# code, the hDevice is not being initialized - POS_SetDeviceParam should initialize it with additional params.
Any suggestions are very welcome!
You will need to use this P/Invoke signature:
[DllImport(EXT_DLL)]
private static extern int POS_SetDeviceParam(
IntPtr hDevice,
int paramCode,
IntPtr paramValue
);
But you'll have to do some work to that string in order to pass it through the IntPtr paramValue argument.
Perhaps you can try using Marshal.StringToHGlobalAnsi() as that will give you an IntPtr you can use. If using this method though be sure to free the memory once you've finished with it.
Thank you guys for all the suggestions, the code below solved my problem!
[DllImport(EXT_DLL)]
private static extern int POS_SetDeviceParam(IntPtr hDevice, UInt32 POSNET_DEV_PARAM_IP, IntPtr paramValue);
void Test() {
POS_SetDeviceParam(new IntPtr(), 0x00020005, Marshal.StringToHGlobalAnsi("192.168.1.1"));
}