PROPID_M_EXTENSION

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. It is the responsibility of the application 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, always inspect the returned value of PROPID_M_EXTENSION_LEN to see if any 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 are using 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++;

Requirements

Runs on Versions Defined in Include Link to
Windows CE OS 2.0 and later. Versions prior to 2.12 require the MSMQ add-on pack. Mq.h    

Note   This API is part of the complete Windows CE OS package as provided by Microsoft. The functionality of a particular platform is determined by the original equipment manufacturer (OEM) and some devices may not support this API.

See Also

MQReceiveMessage, PROPID_M_EXTENSION_LEN, MQMSGPROPS

 Last updated on Tuesday, July 13, 2004

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