INTERRUPT_MESSAGE_INFO Structure

INTERRUPT_MESSAGE_INFO specifies a pointer to a user-allocated buffer which contains a message table and the number of entries in that table.

Syntax

typedef struct _INTERRUPT_MESSAGE_INFO {
	ULONG MessageCount;
	INTERRUPT_MESSAGE_INFO_ENTRY MessageInfo[1];
} INTERRUPT_MESSAGE_INFO, *PINTERRUPT_MESSAGE_INFO;

Members

MessageCount

The number of INTERRUPT_MESSAGE_INFO_ENTRY structures allocated in the MessageInfo table.

MessageInfo

An array of INTERRUPT_MESSAGE_INFO_ENTRY structures. See the code sample below, in which we dynamically allocate a buffer to hold the INTERRUPT_MESSAGE_INFO structure and the out-of-bound elements, fill in the buffer, and call RtAttachInterrupt.

//
	// Determine the size of the messages table.
	//
	// NOTE: "MsgCount" must have been properly defined.
	// It must contain the number of MSI-X messages needed by the application.
	//
	ULONG MsgTableSize = sizeof(INTERRUPT_MESSAGE_INFO) + (MsgCount - 1) * sizeof(INTERRUPT_MESSAGE_INFO_ENTRY);
 
	//
	// Allocate memory for the messages table.
	//
	PINTERRUPT_MESSAGE_INFO MsgTable = (PINTERRUPT_MESSAGE_INFO)RtAllocateLocalMemory(MsgTableSize);
	if (!MsgTable)
	{
		//
		// Handle the error.
		//
	}
 
	//
	// Fill in the messages table.
	//
	ULONG MsgId;
	PINTERRUPT_MESSAGE_INFO_ENTRY MsgInfo;
	for (MsgId=0, MsgInfo=msgTable->MessageInfo; MsgId < MsgCount; MsgId++, MsgInfo++)
	{
		//
		// Here, fill in the following fields based on the needs of your application:
		//
		// MsgInfo->MessageId        = ...
		// MsgInfo->TargetProcessor  = ...
		// MsgInfo->Priority         = ...
		//
	}
	MsgTable->MessageCount = MsgCount;
 
	//
	// Define the parameters for the call to "RtAttachInterrupt".
	//
	// NOTE: "ThreadAttributes", "StackSize", "MultiVectorIST", "MultiVectorISR", "MultiVectorEnableInterrupt",
	// "Context", "BusNumber" and "SlotNumber" must have been properly defined.
	//
	ATTACH_INTERRUPT_PARAMETERS AttachParams =
	{
		.AttachVersion                                           = ATTACH_MESSAGE_BASED_MULTI_VECTOR,
		.MessageBasedMvector.InterruptMessageTable               = MsgTable,
		.MessageBasedMvector.pThreadAttributes                   = ThreadAttributes,
		.MessageBasedMvector.StackSize                           = StackSize,
		.MessageBasedMvector.pRoutine                            = MultiVectorIST,
		.MessageBasedMvector.MyInterrupt                         = MultiVectorISR,
		.MessageBasedMvector.EnableInterruptFromSpecifiedMessage = MultiVectorEnableInterrupt,
		.MessageBasedMvector.Context                             = Context,
		.MessageBasedMvector.BusNumber                           = BusNumber,
		.MessageBasedMvector.SlotNumber                          = SlotNumber,
	};
 
	//
	// Attach the MSI-X multi vector interrupt.
	//
	HANDLE hInterrupt = RtAttachInterrupt(&AttachParams);
	if (!hInterrupt)
	{
		//
		// Handle the error.
		//
	}
 
	//
	// Free the messages table buffer, as it’s no longer needed.
	//
	RtFreeLocalMemory(MsgTable);

Requirements

Minimum Supported Version

RTX64 3.3
Header Rtapi.h

See Also: