Hi there,
I have some doubts about the using of PInvoke to import dll functions.
Let's see
I have a function which returns a pinter to a structure to open a network
adapter

LPADAPTER PacketOpenAdapter(LPTSRT AdapterName);

and i have other which is used to close the adapter and free the adapter
structure

VOID PacketCloseAdapter(LPADAPTER lpAdapter);

the first thing i have done is to define  an adapter structure

[StructLayout(LayoutKind.Sequential,CharSet=CharSet.Auto)]
class LPADAPTER
{
     public IntPtr hFile;
     [MarshalAs(UnmanagedType.ByValTStr,SizeConst=64)]
     public string SymbolicLink;
     public int NumWrites;
     public IntPtr ReadEvent;
     public int ReadTimeout;
}

and do this

[DllImport("packet.dll", CharSet = CharSet.Auto)]
static extern LPADAPTER PacketOpenAdapter(string AdapterName);
[DllImport("packet.dll")]
static extern void PacketCloseAdapter(LPADAPTER lpAdapter);

OK but then i have thinked that if the structure has to be freed by
packetclose adapter then i cannot pass a managed structure and i have to use
IntPtr as well in the DllImports:
[DllImport("packet.dll", CharSet = CharSet.Auto)]
static extern IntPtr PacketOpenAdapter(string AdapterName);
[DllImport("packet.dll")]
static extern void PacketCloseAdapter(IntPtr lpAdapter);

But im not very sure if it is necessary.What is the criteria i have to
follow to decide if i have to use IntPtr's or managed structures???
Thanks