OriginatingOSUser is an optional read-only property of the IMessageSendNames interface that returns the message parameter name expected by the MessageLog2.SendLogMessage method when specifying the user defined property OriginatingOSUser.
An originating O/S user represents the user sending a message as determined by an application. The MessageLog2.SendLogMessage method will automatically add the ProcessOSUser to each log message. However in some cases, such as an application server, the user associated with the application's process may not be the user that the message pertains to. In this case the application may choose to use the OriginatingOSUser property of a message to clearly define the sender or related user of the message.
The object placeholder is an object expression that evaluates to a IMessageSendNames interface.
The IMessageSendNames interface can be obtained directly from the MessageLog2.MessageSendNames property or by using QueryInterface (assignment, in VB, casting in .Net) on a MessageLog or MessageLog2 object.
When adding to the NamedValues collection, the IMessageSendNames interface acts with Intellisense to show the available parameter options and ensures only names that are supported are used.