DllNotFoundException in unity3d plugin for c++ dll

Question

I am working on the Unity Plugin project and try to import the c++ native dll from c# file. But I keep getting dllnotfoundexception.

c++ dll code:

Answer 1

Make sure the following chacklist is satisfied:

• Plugins should all stay in a folder called Plugins.
• The architecture your dll is built for (x86 or x86_64) must correspond to the architecture version of Unity Editor. Unity Editor 32-bit will not load 64 bit plugins and viceversa.
• If you are targeting both 32 and 64 bit architectures you should put your dlls in special named folders inside the Plugins folder. The names are Plugins/x86 for 32 bit dlls and Plugins/x86_64 (x64 also works) for 64 bit dlls.
• Visual C++ Redistributables must be installed. I have all from 2008.
• When you build all your dlls should be copied into the root where your executable is (and again built for the correct x86/x64 architecture)

If you keep getting a namespace error it means the dll you are importing has unmanaged code and it must be wrapped into another managed dll Pugin in order to work.

These threads are a bit outdated but still relevant

DLLNotFoundException - Unity3D Plugin

Unity internal compiler error with custom dll