2.1.5 Order of Execution

Each clause is represented by its predicate, if any, and the clause's actions. When an enabled probe fires, its actions will execute if the predicate evaluates to true or if no predicate is given. Program order determines the order in which actions are executed. Two or more clauses that enable the same probe will also execute in program order.

No other ordering constraints are imposed. It is not uncommon for the output from two distinct probes to appear interspersed or in the opposite order from which the probes fired.