LPC_MESSAGE

2OO1, 14 January

LPC_MESSAGE

typedef struct _LPC_MESSAGE {

  USHORT                  DataLength;
  USHORT                  Length;
  USHORT                  MessageType;
  USHORT                  DataInfoOffset;
  CLIENT_ID               ClientId;
  ULONG                   MessageId;
  ULONG                   CallbackId;

} LPC_MESSAGE, *PLPC_MESSAGE;

Structure LPC_MESSAGE it's a header for all LPC messages. Any LPC message must contains at least 0x18 bytes length for LPC_MESSAGE header.

DataLength

Length of additional data in message. Maximum length of data is 0x130 bytes.

Length

Length of message, including header. Maximum value is 0x148 bytes length.

MessageType

Type of message. This field is filled by system in message transfer process. Can be one of following:

LPC_REQUEST
LPC_REPLY
LPC_DATAGRAM
LPC_LOST_REPLY
LPC_PORT_CLOSED
LPC_CLIENT_DIED
LPC_EXCEPTION
LPC_DEBUG_EVENT
LPC_ERROR_EVENT
LPC_CONNECTION_REQUEST

DataInfoOffset

ClientId

Port's client unique identifier.

MessageId

System set this field to actual value of incremental message counter.

CallbackId

Structure is known also as LPC_MESSAGE_HEADER.

Documented by:

Bo Branten

Tomasz Nowak

Requirements:

Library: ntdll.lib