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) 1991-2011, 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 OpenVMS/Alpha version of this package 33 34-- This package provides low-level support for most tasking features 35 36pragma Polling (Off); 37-- Turn off polling, we do not want ATC polling to take place during tasking 38-- operations. It causes infinite loops and other problems. 39 40with Interfaces.C; 41 42with System.OS_Interface; 43with System.Aux_DEC; 44 45package System.Task_Primitives is 46 pragma Preelaborate; 47 48 type Lock is limited private; 49 -- Should be used for implementation of protected objects 50 51 type RTS_Lock is limited private; 52 -- Should be used inside the runtime system. The difference between Lock 53 -- and the RTS_Lock is that the later one serves only as a semaphore so 54 -- that do not check for ceiling violations. 55 56 type Suspension_Object is limited private; 57 -- Should be used for the implementation of Ada.Synchronous_Task_Control 58 59 type Task_Body_Access is access procedure; 60 -- Pointer to the task body's entry point (or possibly a wrapper 61 -- declared local to the GNARL). 62 63 type Private_Data is limited private; 64 -- Any information that the GNULLI needs maintained on a per-task basis. 65 -- A component of this type is guaranteed to be included in the 66 -- Ada_Task_Control_Block. 67 68 subtype Task_Address is System.Aux_DEC.Short_Address; 69 -- Task_Address is the short version of address defined in System.Aux_DEC. 70 -- To avoid dragging Aux_DEC into tasking packages a tasking specific 71 -- subtype is defined here. 72 73 Task_Address_Size : constant := System.Aux_DEC.Short_Address_Size; 74 -- The size of Task_Address 75 76 Alternate_Stack_Size : constant := 0; 77 -- No alternate signal stack is used on this platform 78 79private 80 81 type Lock is record 82 L : aliased System.OS_Interface.pthread_mutex_t; 83 Prio : Interfaces.C.int; 84 Prio_Save : Interfaces.C.int; 85 end record; 86 87 type RTS_Lock is new System.OS_Interface.pthread_mutex_t; 88 89 type Suspension_Object is record 90 State : Boolean; 91 pragma Atomic (State); 92 -- Boolean that indicates whether the object is open. This field is 93 -- marked Atomic to ensure that we can read its value without locking 94 -- the access to the Suspension_Object. 95 96 Waiting : Boolean; 97 -- Flag showing if there is a task already suspended on this object 98 99 L : aliased System.OS_Interface.pthread_mutex_t; 100 -- Protection for ensuring mutual exclusion on the Suspension_Object 101 102 CV : aliased System.OS_Interface.pthread_cond_t; 103 -- Condition variable used to queue threads until ondition is signaled 104 end record; 105 106 type Private_Data is record 107 Thread : aliased System.OS_Interface.pthread_t; 108 pragma Atomic (Thread); 109 -- Thread field may be updated by two different threads of control. 110 -- (See, Enter_Task and Create_Task in s-taprop.adb). They put the 111 -- same value (thr_self value). We do not want to use lock on those 112 -- operations and the only thing we have to make sure is that they 113 -- are updated in atomic fashion. 114 115 CV : aliased System.OS_Interface.pthread_cond_t; 116 117 L : aliased RTS_Lock; 118 -- Protection for all components is lock L 119 120 AST_Pending : Boolean; 121 -- Used to detect delay and sleep timeouts 122 123 end record; 124 125end System.Task_Primitives; 126