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4/8/2010

This property indicates which transaction sent the message.

Property ID

PROPID_M_XACTID

Type Indicator

VT_VECTOR | VT_UI1

MQPROPVARIANT Field

caub

Property Values

Identifier of the transaction.

For a description of a transaction identifier, see the Remarkssection.

Remarks

This property is available for MSMQ 2.0 and later.

It is used by receiving applications to verify that a message was sent from a specific transaction.

The transaction identifier is a 20-byte identifier that includes the following:

  • The computer identifier of the sending machine (the first 16 bits)

  • A transaction sequence number (the last 4 bytes)

Transaction identifiers are not guaranteed to be unique because the transaction sequence numbers are not persistent and they start over again at 2^20.

Message Queuing guarantees only that subsequent transactions will have different transaction sequence numbers.

To verify transaction boundaries, use PROPID_M_XACTID with the following properties:

Examples

The following code example shows how PROPID_M_XACTID is specified in the MQMSGPROPSstructure.

Copy Code 
DWORD dwIdBufferSize = 1024;
UCHAR *pucIdBuffer = (UCHAR *)malloc(dwIdBufferSize);
if (pucIdBuffer == NULL) {
	// Error handling code (not included for clarity)
}
aMsgPropId[i] = PROPID_M_XACTID; // Property ID
aPropVar[i].vt = VT_VECTOR|VT_UI1; // Type indicator
aPropVar[i].caub.pElems = (UCHAR*)pucIdBuffer;
aPropVar[i].caub.cElems = dwIdBufferSize;
i++;

See Also