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------------------------------------------------------------------------------
-- --
-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
-- --
-- S Y S T E M . T A S K _ P R I M I T I V E S --
-- --
-- S p e c --
-- --
-- Copyright (C) 1992-2011, Free Software Foundation, Inc. --
-- --
-- GNARL is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 3, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. --
-- --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception, --
-- version 3.1, as published by the Free Software Foundation. --
-- --
-- You should have received a copy of the GNU General Public License and --
-- a copy of the GCC Runtime Library Exception along with this program; --
-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
-- <http://www.gnu.org/licenses/>. --
-- --
-- GNARL was developed by the GNARL team at Florida State University. --
-- Extensive contributions were provided by Ada Core Technologies, Inc. --
-- --
------------------------------------------------------------------------------
-- This is a Solaris version of this package
-- This package provides low-level support for most tasking features
pragma Polling (Off);
-- Turn off polling, we do not want ATC polling to take place during tasking
-- operations. It causes infinite loops and other problems.
with Ada.Unchecked_Conversion;
with System.OS_Interface;
package System.Task_Primitives is
pragma Preelaborate;
type Lock is limited private;
type Lock_Ptr is access all Lock;
-- Should be used for implementation of protected objects
type RTS_Lock is limited private;
type RTS_Lock_Ptr is access all RTS_Lock;
-- Should be used inside the runtime system. The difference between Lock
-- and the RTS_Lock is that the later one serves only as a semaphore so
-- that do not check for ceiling violations.
function To_Lock_Ptr is
new Ada.Unchecked_Conversion (RTS_Lock_Ptr, Lock_Ptr);
type Suspension_Object is limited private;
-- Should be used for the implementation of Ada.Synchronous_Task_Control
type Task_Body_Access is access procedure;
-- Pointer to the task body's entry point (or possibly a wrapper
-- declared local to the GNARL).
type Private_Data is limited private;
-- Any information that the GNULLI needs maintained on a per-task basis.
-- A component of this type is guaranteed to be included in the
-- Ada_Task_Control_Block.
subtype Task_Address is System.Address;
-- In some versions of Task_Primitives, notably for VMS, Task_Address is
-- the short version of address defined in System.Aux_DEC. To avoid
-- dragging Aux_DEC into tasking packages a tasking specific subtype is
-- defined here.
Task_Address_Size : constant := Standard'Address_Size;
-- The size of Task_Address
Alternate_Stack_Size : constant := 0;
-- No alternate signal stack is used on this platform
private
type Private_Task_Serial_Number is mod 2 ** 64;
-- Used to give each task a unique serial number
type Base_Lock is new System.OS_Interface.mutex_t;
type Owner_Int is new Integer;
for Owner_Int'Alignment use Standard'Maximum_Alignment;
type Owner_ID is access all Owner_Int;
function To_Owner_ID is
new Ada.Unchecked_Conversion (System.Address, Owner_ID);
type Lock is record
L : aliased Base_Lock;
Ceiling : System.Any_Priority := System.Any_Priority'First;
Saved_Priority : System.Any_Priority := System.Any_Priority'First;
Owner : Owner_ID;
Next : Lock_Ptr;
Level : Private_Task_Serial_Number := 0;
Buddy : Owner_ID;
Frozen : Boolean := False;
end record;
type RTS_Lock is new Lock;
type Suspension_Object is record
State : Boolean;
pragma Atomic (State);
-- Boolean that indicates whether the object is open. This field is
-- marked Atomic to ensure that we can read its value without locking
-- the access to the Suspension_Object.
Waiting : Boolean;
-- Flag showing if there is a task already suspended on this object
L : aliased System.OS_Interface.mutex_t;
-- Protection for ensuring mutual exclusion on the Suspension_Object
CV : aliased System.OS_Interface.cond_t;
-- Condition variable used to queue threads until condition is signaled
end record;
-- Note that task support on gdb relies on the fact that the first two
-- fields of Private_Data are Thread and LWP.
type Private_Data is record
Thread : aliased System.OS_Interface.thread_t;
pragma Atomic (Thread);
-- Thread field may be updated by two different threads of control.
-- (See, Enter_Task and Create_Task in s-taprop.adb). They put the same
-- value (thr_self value). We do not want to use lock on those
-- operations and the only thing we have to make sure is that they are
-- updated in atomic fashion.
LWP : System.OS_Interface.lwpid_t;
-- The LWP id of the thread. Set by self in Enter_Task
CV : aliased System.OS_Interface.cond_t;
L : aliased RTS_Lock;
-- Protection for all components is lock L
Active_Priority : System.Any_Priority := System.Any_Priority'First;
-- Simulated active priority, used iff Priority_Ceiling_Support is True
Locking : Lock_Ptr;
Locks : Lock_Ptr;
Wakeups : Natural := 0;
end record;
end System.Task_Primitives;
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