Solved it! The simple answer was to declare a variable as POINTER TO STRING and assign the GetMessage result to that variable. Then, the ^ operator can be used to extract the message as string.
I am trying to implement a mechanism to send alarm SMS. For this, I have created an Alarm Class with a Notification Action which calls a POU. This POU implements IAlarmNotifiable making it selectable in the Alarm Class configuration. IAlarmNotifiable has an Execute method which is called by the alarm class. Now, I want to extract the alarm message of the triggered alarm. The Execute method comes with a VAR_INPUT itfAlarm: AlarmManager.IAlarm which supplies a method called GetMessage. The help text...