In a real-time environment at least one task is executed with a pre-defined task run-time, wherein at least one auxiliary function with indeterminate function run-time is to be processed within the specified task run-time by means of a time monitoring function. The time monitoring function, which defines a termination time for the auxiliary function within the pre-defined task run-time, is started. Then the auxiliary function is executed, wherein the time monitoring function monitors the function run-time and a function abort is initiated if the pre-defined abort time point is exceeded. Finally, the time monitoring function is terminated.