If you are going to call Marshal.GetLastWin32Error, the function whose error you’re retrieving had better have SetLastError=true

Raymond ChenAugust 18, 2015Aug 18, 201508/18/15

A customer reported that their p/invoke to a custom DLL was failing, and the error code made no sense. The customer reported that their Fribble function was returning −1, indicating a failure to open the event, but the error code returned by Marshal.Get­Last­Win32­Error is 87, "The parameter is incorrect." But all of the ...