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DllNotFoundException when C# code tries to pinvoke a native lib
Egorbo
✭
I have an UWP C# project that uses a native lib (my-lib.dll) written in C++ for UWP. The my-lib.dll is added to the C# project as a Content with "Copy always", and when I call a method with [DllImport("my-lib")] - it works fine for Desktop UWP (local machine) but when I deploy it to a HoloLense emulator -- it crashes with DllNotFoundException (Unable to load DLL 'my-lib': The specified module could not be found. (Exception from HRESULT: 0x8007007E)) on that pinvoke. Is there something I forgot to do with my-lib.dll? Thanks in advance.
But it looks like it's there because this code:var hasNativeLib = (await Package.Current.InstalledLocation.GetFilesAsync()).Any(f => f.Name == "my-lib.dll")
returns true when deployed to Hololens emulator
Lib:
my-lib.dll is a dynamic library x86 compiled via default UWP C++ template.
Environment:
VS2015 UPDATE 3, Emulator 10.0.14342.1018. Target & Min Platform: 10.0.10586.0 (in C# and C++).
Best Answer
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Options
TimK
mod
Are you sure all the dependencies for your DLL are also deployed with your project?
Specifically, the C-Runtime DLLs e.g. msvcp140.dll, vccorlib140.dll, etc. since the DllNotFoundException means the target dll or one of its dependencies wasn’t found.
Your desktop PC has these DLLs installed as part of the Visual Studio Redistributables, but the emulator (and possibly the HoloLens device) do not have the redists and so will hit this error.
5
Answers
Are you sure all the dependencies for your DLL are also deployed with your project?
Specifically, the C-Runtime DLLs e.g. msvcp140.dll, vccorlib140.dll, etc. since the DllNotFoundException means the target dll or one of its dependencies wasn’t found.
Your desktop PC has these DLLs installed as part of the Visual Studio Redistributables, but the emulator (and possibly the HoloLens device) do not have the redists and so will hit this error.
Are you sure all the dependencies for your DLL are also deployed with your project?
Specifically, the C-Runtime DLLs e.g. msvcp140.dll, vccorlib140.dll, etc. since the DllNotFoundException means the target dll or one of its dependencies wasn’t found.
Your desktop PC has these DLLs installed as part of the Visual Studio Redistributables, but the emulator (and possibly the HoloLens device) do not have the redists and so will hit this error.
Are you sure all the dependencies for your DLL are also deployed with your project?
Specifically, the C-Runtime DLLs e.g. msvcp140.dll, vccorlib140.dll, etc. since the DllNotFoundException means the target dll or one of its dependencies wasn’t found.
Your desktop PC has these DLLs installed as part of the Visual Studio Redistributables, but the emulator (and possibly the HoloLens device) do not have the redists and so will hit this error.
@TimK thanks, Tim! Actually ucrtbased.dll (debug mode) was missing
could you tell us how you found out which dll was missing?