1------------------------------------------------------------------------------ 2-- -- 3-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS -- 4-- -- 5-- S Y S T E M . T A S K _ P R I M I T I V E S -- 6-- -- 7-- S p e c -- 8-- -- 9-- Copyright (C) 2001-2019, Free Software Foundation, Inc. -- 10-- -- 11-- GNARL is free software; you can redistribute it and/or modify it under -- 12-- terms of the GNU General Public License as published by the Free Soft- -- 13-- ware Foundation; either version 3, or (at your option) any later ver- -- 14-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- 15-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- 16-- or FITNESS FOR A PARTICULAR PURPOSE. -- 17-- -- 18-- As a special exception under Section 7 of GPL version 3, you are granted -- 19-- additional permissions described in the GCC Runtime Library Exception, -- 20-- version 3.1, as published by the Free Software Foundation. -- 21-- -- 22-- You should have received a copy of the GNU General Public License and -- 23-- a copy of the GCC Runtime Library Exception along with this program; -- 24-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- 25-- <http://www.gnu.org/licenses/>. -- 26-- -- 27-- GNARL was developed by the GNARL team at Florida State University. -- 28-- Extensive contributions were provided by Ada Core Technologies, Inc. -- 29-- -- 30------------------------------------------------------------------------------ 31 32-- This is a VxWorks version of this package 33 34pragma Polling (Off); 35-- Turn off polling, we do not want ATC polling to take place during tasking 36-- operations. It causes infinite loops and other problems. 37 38with System.OS_Interface; 39 40package System.Task_Primitives is 41 pragma Preelaborate; 42 43 type Lock is limited private; 44 -- Should be used for implementation of protected objects 45 46 type RTS_Lock is limited private; 47 -- Should be used inside the runtime system. The difference between Lock 48 -- and the RTS_Lock is that the later one serves only as a semaphore so 49 -- that do not check for ceiling violations. 50 51 type Suspension_Object is limited private; 52 -- Should be used for the implementation of Ada.Synchronous_Task_Control 53 54 type Task_Body_Access is access procedure; 55 -- Pointer to the task body's entry point (or possibly a wrapper 56 -- declared local to the GNARL). 57 58 type Private_Data is limited private; 59 -- Any information that the GNULLI needs maintained on a per-task basis. 60 -- A component of this type is guaranteed to be included in the 61 -- Ada_Task_Control_Block. 62 63 subtype Task_Address is System.Address; 64 Task_Address_Size : constant := Standard'Address_Size; 65 -- Type used for task addresses and its size 66 67 Alternate_Stack_Size : constant := 0; 68 -- No alternate signal stack is used on this platform 69 70private 71 72 type Priority_Type is (Prio_None, Prio_Protect, Prio_Inherit); 73 74 type Lock is record 75 Mutex : System.OS_Interface.SEM_ID; 76 Protocol : Priority_Type; 77 78 Prio_Ceiling : System.OS_Interface.int; 79 -- Priority ceiling of lock 80 end record; 81 82 type RTS_Lock is new Lock; 83 84 type Suspension_Object is record 85 State : Boolean; 86 pragma Atomic (State); 87 -- Boolean that indicates whether the object is open. This field is 88 -- marked Atomic to ensure that we can read its value without locking 89 -- the access to the Suspension_Object. 90 91 Waiting : Boolean; 92 -- Flag showing if there is a task already suspended on this object 93 94 L : aliased System.OS_Interface.SEM_ID; 95 -- Protection for ensuring mutual exclusion on the Suspension_Object 96 97 CV : aliased System.OS_Interface.SEM_ID; 98 -- Condition variable used to queue threads until condition is signaled 99 end record; 100 101 type Private_Data is limited record 102 Thread : aliased System.OS_Interface.t_id := 0; 103 pragma Atomic (Thread); 104 -- Thread field may be updated by two different threads of control. 105 -- (See, Enter_Task and Create_Task in s-taprop.adb). 106 -- They put the same value (thr_self value). We do not want to 107 -- use lock on those operations and the only thing we have to 108 -- make sure is that they are updated in atomic fashion. 109 110 LWP : aliased System.OS_Interface.t_id := 0; 111 -- The purpose of this field is to provide a better tasking support on 112 -- gdb. The order of the two first fields (Thread and LWP) is important. 113 -- On targets where lwp is not relevant, this is equivalent to Thread. 114 115 CV : aliased System.OS_Interface.SEM_ID; 116 117 L : aliased RTS_Lock; 118 -- Protection for all components is lock L 119 end record; 120 121end System.Task_Primitives; 122