hi ,i create Lister that will run list of programs from c# application
i can connect the dll ,no problem
but i dont see the function "mcGetInstance" in the API
how i get the current instance

There is no mcGetInstance() in the C API.  That is a LUA only function call so that there is a way to know what instance of Mach called the embedded script.  With C/C++, C#, and VB, you (the programmer) must specify the instance with which to operate.  Mach Hobby only has one instance; instance zero.  So...  in your case, use 0 for the instance. 

Steve