Pfthb

I have used DllImport in the past, but I am having a lot of trouble trying to figure out the correct way to declare and use a particular method due to the parameter types. Here is the C++ prototype:

// PTRobot_EnumRobots
//
// Description:
// Function to enumerate the Robots on the system.
// Params:
// phRobots points to an array of HANDLEs to store
// the Robots found.
// pdwNumRobots points to a DWORD containing the number of HANDLEs
// in the phRobots array. This value is an input
// and an output. The user should specify the size
// (number of HANDLEs) of the phRobots array on input.
// The value of the pdwNumRobots on output will be the
// number of robots found.
//
// Notes:
// Both params will be updated upon successful completion of this
// command. phRobots will contain handles to robots connected to
// this system. pdwNumRobots will will be updated with the number of 
// robots found.
// Also, note that the hDrives array in the PTRobotInfo will not be
// valid until PTRobot_EnumDrives is called.
//
// Return:
// PTROBOT_OK if Successful
// PTROBOT_INVALID_ROBOT if no robots found
// PTROBOT_SEQUENCE if this command is called out of sequence
// PTROBOT_INTERNAL if an internal error occurred
// PTROBOT_OVERFLOW if the number of robots found is > the value in 
// pdwNumRobots
//
///////////////////////////
DWORD WINAPI PTRobot_EnumRobots(HANDLE * phRobots, DWORD * pdwNumRobots);

And here is the C++ usage:

HANDLE hRobots[10];
DWORD dwRet=0, dwRobots=10;

dwRet = PTRobot_EnumRobots(hRobots, &dwRobots);

Here is my attempt at declaring it in C#:

[DllImport("PTRobot.dll", CharSet = CharSet.Unicode)]
private static extern uint PTRobot_EnumRobots(ref IntPtr phRobots, ref uint pdwNumRobots);

usage:

IntPtr robotArray = new IntPtr[1];
UInt32 numRobots = 1;

status = PTRobotDLL.EnumRobots(ref robotArray, ref numRobots);

but I don't think that is right, because I keep getting "INVALID_ROBOT" returned, even though the method return "OK" in C++. I believe the issue is when it is trying to write back to those references, probably because I am not sure how to declare them.

Any insight into the proper way to declare the method in C#? especially with the odd HANDLE array reference?