The OriginatingHost property of the LogMessage2 object is a Read-Only string that represents the machine sending a message as determined by an application. The MessageLog2.SendLogMessage method will automatically add the ProcessHost to any log message sent to a PI server's Message log (remote messages). When sending messages to the local log it is assumed the process host is the same as the host of the PI Message subsystem and this parameter is not logged. However in some cases, such as an application server, the machine where the application is running (the process host) may not be the machine that the message pertains to. In this case the application may choose to use the OriginatingHost property of a message to clearly define the source of the message.
The object placeholder is an object expression that evaluates to a LogMessage2 object.