PROPID_M_EXTENSION
A version of this page is also available for
4/8/2010
This property provides a place to put additional application-defined information that is associated with the message.
- Type Indicator
VT_UI1 | VT_VECTOR
- PROPVARIANT Field
caub
- Property Values
Array of bytes
Remarks
The PROPID_M_EXTENSION property is typically used by applications that need to specify or read non-MSMQ message properties when working with foreign queues.
The application is responsible to understand the content of this property.
To send extension information, specify PROPID_M_EXTENSION in the MQMSGPROPS structure and call MQSendMessage.
To retrieve extension information, specify PROPID_M_EXTENSION and PROPID_M_EXTENSION_LEN in the MQMSGPROPS structure. Then call MQReceiveMessage and examine the returned values.
Before using the returned value of PROPID_M_EXTENSION, inspect the returned value of PROPID_M_EXTENSION_LENto see if extension information was sent.
A returned value of 0 indicates that no information was sent by the sending application.
A nonzero returned value indicates the extension information was returned by PROPID_M_EXTENSION.
This property is not available when you use COM components.
Examples
The following examples show how PROPID_M_EXTENSION is specified in the MQMSGPROPS structure for sending and retrieving extension information.
To send extension information
aMsgPropId[i] = PROPID_M_EXTENSION; // Property ID
aMsgPropVar[i].vt = VT_UI1 | VT_VECTOR; // Type indicator
aMsgPropVar[i].caub.pElems = ExtensionInformation;
aMsgPropVar[i].caub.cElems = sizeof(ExtensionInformation);
i++;
To retrieve extension information
aMsgPropId[i] = PROPID_M_EXTENSION_LEN; // Property ID
aMsgPropVar[i].vt = VT_UI4; // Type indicator
i++;
aMsgPropId[i] = PROPID_M_EXTENSION; // Property ID
aMsgPropVar[i].vt = VT_UI1 | VT_VECTOR; // Type indicator
i++;
Note
OS versions prior to 2.12 require the MSMQ add-on pack.
Requirements
| Header | mq.h |
| Windows Embedded CE | Windows CE 2.0 and later |
| Windows Mobile | Windows Mobile Version 5.0 and later |