问2 **指针的C# PInvoke

EN

//C Function: GetInformatiuon(...)
ERROR GetInformatiuon(
    Component comp, 
    struct Information** Info);

//C# Function: GetInformatiuon(...)
[DllImport("externalSDK.dll", EntryPoint = "GetInformatiuon", CallingConvention = CallingConvention.Cdecl)]
    public static extern ERROR GetInformatiuon(Component comp, ref Information Info);
);

//C Enum: ERROR 
typedef enum ERROR_E {
    OK = 0, //Everything is ok
    E_ARG = 1, //Error in the Arguments 
    E_DATA = 2 //Data error
    //And more...
 } ERROR;

 //C# Enum: ERROR
 public enum ERROR
 {
    OK = 0, //Everything is ok
    E_ARG = 1, //Error in the Arguments 
    E_DATA = 2 //Data error
    //And more...
 }

//C struct: Component
typedef struct Component_S
{
    void* ObjPointer;    
    unsigned long number; 
} Component;

//C# class: Component
[StructLayout(LayoutKind.Sequential)]
public class Component
{
    public IntPtr ObjPointer;
    public uint number; //uint because usigned long C is 4 bytes (32 bits) and C# ulong is 8 bytes (64 bits), where C# uint is 4 bytes(32 bits)
}

 //C struct: Information
 typedef struct Information_S {
   char* language;           
   unsigned long sampleFrequency;  
   unsigned long frameShift;       
 }Information;

//C# struct: Information
[StructLayout(LayoutKind.Sequential)]
public struct Information
{
    public string language;   
    public uint sampleFrequency;  //uint because usigned long C is 4 bytes (32 bits) and C# ulong is 8 bytes (64 bits), where C# uint is 4 bytes(32 bits)
    public uint frameShift;       //uint because usigned long C is 4 bytes (32 bits) and C# ulong is 8 bytes (64 bits), where C# uint is 4 bytes(32 bits)
}