pInvokeStackImbalance MDA Warning and how to turn it off or fix it

    [DllImport( "zlib32" )]开发者_Go百科
    private static extern ZLibError compress2( 
                byte[] dest,
                ref int destLength, 
                byte[] source, 
                int sourceLength, 
                ZLibQuality quality 
            );

every time I call this I get an MDA warning telling me the stack is imbalanced, which is a nightmare for debugging. I want to either turn this warning off, or fix the issue

This MDA raised to tell you that you have a problem with parameters type you are using for PInvoke call. Generally, it is very bad idea to turn it off since it warns about problem in your code and imbalanced stack leads to errors (sometimes hard to find) in future.

Usually, common mistake is selected matching for unmanaged type with managed one.

In your case, original defininition (I take a look to zlib125.zip):

ZEXTERN int ZEXPORT compress2 OF((Bytef *dest,   uLongf *destLen,
                                  const Bytef *source, uLong sourceLen,
                                  int level)); 

which can be traslated to if library was compiled with 64-bit support for unsigned long:

static int compress2(
    byte[] dest,
    ref ulong destLength,
    byte[] source,
    ulong sourceLength,
    int level)

Ensure ZLibQualityenumeration is based on int. Probably, your error is usage int instead of ulong for both lengths.

As stated David Heffernan there are plenty other reasons to fail to find exact one give us link to library actually used for development if you still want to know.

• traditional compilation original library with Visual C++ will result you get library with 32-bit support only, so original definition you provided in question is valid unless ZLibQuality enumeration is not int based

• maybe you try to use library compiled for other calling convention such as cdecl instead of stdcall

• maybe you try to use modified library where compress2 function takes additional parameters.

We can find whats wrong when we can see exact library you are using.

long or unsigned long usually 32-bit under Windows and mapped to int or uint respectively. Since you have troubles with original declaration I assumed that maybe you are using specific library with 64-bit support. Thanks to David Heffernan to point me makes my notice clearly.

You can use folowing resourses as reference:

• A wiki for .NET developers - PInvoke.net is primarily a wiki, allowing developers to find, edit and add PInvoke* signatures, user-defined types, and any other information related to calling Win32 and other unmanaged APIs from managed code

• PInvoke Interop Assistant

/Offtopic:

Why do you use you own implementation with self bindings to library? You can use:

• DotNetZip - Zip and Unzip in C#, VB, any .NET language - DotNetZip is an easy-to-use, FAST, FREE class library and toolset for manipulating zip files or folders. Zip and Unzip is easy: with DotNetZip, .NET applications written in VB, C# - any .NET language - can easily create, read, extract, or update zip files. For Mono or MS .NET.

• or ready to use 7-zip bindings: SevenZipSharp - Managed 7-zip library written in C# that provides data (self-)extraction and compression (all 7-zip formats are supported). It wraps 7z.dll or any compatible one and makes use of LZMA SDK.

The stack imbalance is because you have mis-matching calling conventions or mis-matching function declarations. I'd be very surprised if zlib32 was using stdcall calling convention. Surely that uses cdecl. I'd want to see your C++ declaration of that function before giving firmer advice.

Leave the warning on because it's finding bugs in your code, and fix the mis-matches, whatever they are.

There could be a real issue here, but I usually have to disable all Managed Debugging Assistants every now and then, since some of these magically get enabled. Be sure to check Debug | Exceptions node, then expand the Managed Debugging Assistants and make sure every one of these is disabled.

EDIT: You will have better luck replacing the P/Invoke with a C++/CLI wrapper that you create for compress2.