The Ravenscar profile is a subset of the Ada

Ada (programming language)

Ada is a structured, statically typed, imperative, wide-spectrum, and object-oriented high-level computer programming language, extended from Pascal and other languages...

 tasking features designed for safety-critical hard real-time computing

Real-time computing

In computer science, real-time computing , or reactive computing, is the study of hardware and software systems that are subject to a "real-time constraint"— e.g. operational deadlines from event to system response. Real-time programs must guarantee response within strict time constraints...

. It was defined by a separate technical report in Ada 95; it is now part of the Ada 2005 Standard.

Restrictions of the profile

A Ravenscar Ada application uses the following compiler directive

Directive (programming)

In computer programming, the term directive is applied in a variety of ways that are similar to the term command. It is also used to describe some programming language constructs ....

:

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);

External links

• The Ravenscar Profile, by Paul Parkinson