This property specifies the length of the information in the PROPID_M_EXTENSION property.
- Type Indicator
VT_UI4 (or VT_NULL)
- PROPVARIANT Field
- Property Values
The size (in bytes) of the extension information specified by PROPID_M_EXTENSION.
PROPID_M_EXTENSION_LEN is used only by the receiving application. It is used whenever the receiving application specifies PROPID_M_EXTENSION in the MQMSGPROPS structure.
To retrieve extension information, set PROPID_M_EXTENSION and PROPID_M_EXTENSION_LEN in the MQMSGPROPS structure. Then call MQReceiveMessage and examine the returned values. When specifying PROPID_M_EXTENSION_LEN, you can set its Type Indicator to VT_NULL. When the Type Indicator is set to VT_NULL, MSMQ sets the VT field to the appropriate type indicator.
When MQReceiveMessage succeeds, first test the returned value of PROPID_M_EXTENSION_LEN to see if any extension information exists. 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.
If MQReceiveMessage fails, returning an MQ_ERROR_BUFFER_OVERFLOW error, use the returned value of PROPID_M_EXTENSION_LEN to reallocate the extension information buffer and call MQReceiveMessage again.
This property is not needed when you are using COM components.
This example shows how PROPID_M_EXTENSION_LEN and PROPID_M_EXTENSION are specified in the MQMSGPROPS structure.
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++;
|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.
Last updated on Tuesday, July 13, 2004
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