PROPID_M_LABEL (Windows CE 5.0)
This property specifies a label of the message.
- Type Indicator
VT_LPWSTR - PROPVARIANT Field
pwszVal - Property Values
Arbitrary string (the default is none). The maximum length is 250 Unicode characters, including the end-of-string character.
Remarks
If the sending application specifies a message label longer than 250 Unicode characters, MSMQ returns an MQ_ERROR_LABEL_TOO_LONG error to the aStatus array.
To add a label to a message, specify PROPID_M_LABEL in the MQMSGPROPS structure and call MQSendMessage.
To retrieve the label of a message, specify PROPID_M_LABEL_LEN and PROPID_M_LABEL in the MQMSGPROPS structure. Then call MQReceiveMessage and examine the returned values.
Before using the returned value, inspect the returned value of PROPID_M_LABEL_LEN to see if the sending application specified a message label.
A returned value of 0 indicates that no label was specified by the sending application.
A nonzero returned value indicates that the label was returned by PROPID_M_LABEL.
Examples
The following examples show how PROPID_M_LABEL is specified in the MQMSGPROPS structure for setting and retrieving the message label.
To send a message label
aMsgPropId[i] = PROPID_M_LABEL; // PropId
aMsgPropVar[i].vt = VT_LPWSTR; // Type
aMsgPropVar[i].pwszVal = L"Test Message"; // Value
i++;
To retrieve the message label
aMsgPropId[i] = PROPID_M_LABEL_LEN; // Property ID
aMsgPropVar[i].vt =VT_UI4; // Type indicator
aMsgPropVar[i].ulVal = 250; // Label buffer size
i++;
aMsgPropId[i] = PROPID_M_LABEL; // Property ID
aMsgPropVar[i].vt = VT_LPWSTR; // Type indicator
aMsgPropVar[i].pwszVal = wszLabelBuffer; // Label buffer
i++;
Requirements
OS Versions: Windows CE 2.0 and later. Versions prior to 2.12 require the MSMQ add-on pack.
Header: Mq.h.
See Also
MQReceiveMessage | MQSendMessage | PROPID_M_LABEL_LEN | MQMSGPROPS
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