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POExporting functions from C++ dll to C# P/Invoke
 

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    <p>I have built a C++ dll that I would like to call from C# code. I'm able to call one function, but the other throws an exception when the C# code tries to load the dll.</p> <p>The header looks like this:</p> <pre><code>extern "C" __declspec(dllexport) BOOL Install(); extern "C" __declspec(dllexport) BOOL PPPConnect(); </code></pre> <p>This produces a dll with slightly confusing exports table (what does foo = foo mean in the name field?):</p> <pre><code>File Type: DLL Section contains the following exports for PPPManager.dll 00000000 characteristics 499F44F0 time date stamp Fri Feb 20 16:04:00 2009 0.00 version 1 ordinal base 2 number of functions 2 number of names ordinal hint RVA name 1 0 000078E4 Install = Install 2 1 000079DC PPPConnect = PPPConnect </code></pre> <p>My P/Invoke declarations look like this:</p> <pre><code>[DllImport("PPPManager.dll")] private static extern bool Install(); [DllImport("PPPManager.dll")] private static extern bool PPPConnect(); </code></pre> <p>The call to Install returns with no exception, but when I call PPPConnect, I get a MissingMethodException - "Can't find an Entry Point 'PPPConnect' in a PInvoke DLL 'PPPManager.dll'."</p> <p>I've tried removing the extern and declspec directives from the Install function declaration, so that PPPConnect is the only function exported, and this still doesn't let me call PPPConnect.</p> <p>I have also tried doing the DllImport by ordinal; this gives the same result as calling by name - Install returns, but PPPConnect throws the exception "Can't find an Entry Point '#2'...".</p> <p>The interop log gives:</p> <pre><code>[pinvokeimpl][preservesig] bool invivodata.Common.System.IPAQUtils::Install(); BOOLEAN (I1_WINBOOL_VAL) Install(); JIT ERROR FOR PINVOKE METHOD (Managed -&gt; Native): [pinvokeimpl][preservesig] bool invivodata.Common.System.IPAQUtils::PPPConnect(); BOOLEAN (I1_WINBOOL_VAL) PPPConnect(); </code></pre> <p>This is well outside my area of expertise, so any suggestions or thoughts would be welcome.</p> <p>Thanks, Paul</p> <p>edit: It turns out that this code does work; the problem was with the latest dll not being propagated to the device. D'oh!</p>
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    1. COI've never heard of this interop log - how does one enable/view that?
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    2. COhttp://blogs.msdn.com/netcfteam/archive/2005/07/24/442609.aspx I just started using it to try and debug this problem, but it seems like it would have saved me a lot of time debugging MissingMethodExceptions.
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