Hallo to everyone,
I have a dll called (picboot.dll) written in c++ that works in a vb6 project.
I'm trying to convert the vb project in c#.

PacketData is a byte array parameter, that reads and writes  bytes to the
dll, calling the functions ReadPic and WritePic .

I've started with the new project in c#, and i've used dllimport directive
to use the dll in the project.
I've used the byte[] type to marshal the type of the dll.
The result is that ReadPIC function works fine, and I can get the PacketData
byte array.
The WRITEPIC doesn't return errors, but seems to write strange data.
The question is:
I know very little about unsafe code, and "fixed" statements, and I'd like
to know how is the right way to pass the value to the dll function.

Original in visual basic 6 (working):
Public Declare Function ReadPIC Lib "PICBOOT.dll" (ByVal hComPort As Long,
LPpic As PIC, PacketData As Byte) As Integer
Public Declare Function WritePIC Lib "PICBOOT.dll" (ByVal hComPort As Long,
LPpic As PIC, PacketData As Byte) As Integer

C++ declaration of the api entries defined in the dll:
INT APIENTRY ReadPIC(HANDLE hComPort, PIC *pic, BYTE PacketData[]);
INT APIENTRY WritePIC(HANDLE hComPort, PIC *pic, BYTE PacketData[]);

Declaration in VC#
[DllImport("PICBOOT.dll")]
private static extern int ReadPIC(int hComPort, ref PIC pic, byte[]
PacketData);
[DllImport("PICBOOT.dll")]
private static extern int WritePIC(int hComPort, ref PIC pic, byte[]
PacketData);

Any informations will be appreciated
Thanks in advance,
Marco Roello