Ravenscar profile

From Wikipedia, the free encyclopedia

The Ravenscar profile is a subset of the Ada tasking features designed for safety-critical hard real-time systems.

[edit] Restrictions of the profile

A Ravenscar Ada application uses the following compiler directive:

pragma Profile (Ravenscar);

This is the same as writing the following set of configuration pragmas:

pragma Task_Dispatching_Policy (FIFO_Within_Priorities);

pragma Locking_Policy (Ceiling_Locking);

pragma Detect_Blocking;

pragma Restrictions (
                No_Abort_Statements,
                No_Dynamic_Attachment,
                No_Dynamic_Priorities,
                No_Implicit_Heap_Allocations,
                No_Local_Protected_Objects,
                No_Local_Timing_Events,
                No_Protected_Type_Allocators,
                No_Relative_Delay,
                No_Requeue_Statements,
                No_Select_Statements,
                No_Specific_Termination_Handlers,
                No_Task_Allocators,
                No_Task_Hierarchy,
                No_Task_Termination,
                Simple_Barriers,
                Max_Entry_Queue_Length => 1,
                Max_Protected_Entries  => 1,
                Max_Task_Entries       => 0,
                No_Dependence => Ada.Asynchronous_Task_Control,
                No_Dependence => Ada.Calendar,
                No_Dependence => Ada.Execution_Time.Group_Budget,
                No_Dependence => Ada.Execution_Time.Timers,
                No_Dependence => Ada.Task_Attributes);