systemOptionsMask
nAttnMsg 0x00000001 give this message priority
priorityMask 0x000000FF
nReturnReceipt 0x00000200 return receipt requested
systemOptionsMask 0x00000F00
receiverIDisTargetID 0x00005000 ID is target ID
receiverIDisSessionID 0x00006000 ID is PPC session ID
receiverIDisSignature 0x00007000 ID is creator signature
receiverIDisPSN 0x00008000 ID is process serial num
receiverIDMask 0x0000F000
When you specify the receiving application in the receiverID parameter of
these specifications allows you to send an event to another application on the
local machine. To send events to an application on a remote machine, you can
specify the recipient only by the sessionID or targetID.