Question

I have a C# program that uses a class from another assembly, and this class calls an unmanaged DLL to do some processing. Here is a snippet:

public class Util {     const string dllName = 'unmanaged.dll';     [DllImport(dllName, EntryPoint = 'ExFunc')]     unsafe static extern bool ExFunc(StringBuilder path, uint field);      public bool Func(string path, uint field)     {         return ExFunc(new StringBuilder(path), field);     }      ... }  Util util = new Util(); bool val = util.Func('/path/to/something/', 1); 

The problem I’m having is that if I call ‘Func’ my main C# program will not unload. When I call Close() inside my main form the process will still be there if I look in Task Manager. If I remove the call to ‘Func’ the program unloads fine. I have done some testing and the programs Main function definitely returns so I’m not sure what’s going on here.

Answer 1

Do you have the source code to unmanaged.dll ? It must be doing something, either starting another thread and not exiting, or blocking in it’s DllMain, etc.