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) 1991-2012, 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 HP-UX 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 System.OS_Interface; 41 42package System.Task_Primitives is 43 pragma Preelaborate; 44 45 type Lock is limited private; 46 -- Should be used for implementation of protected objects 47 48 type RTS_Lock is limited private; 49 -- Should be used inside the runtime system. The difference between Lock 50 -- and the RTS_Lock is that the later one serves only as a semaphore so 51 -- that do not check for ceiling violations. 52 53 type Suspension_Object is limited private; 54 -- Should be used for the implementation of Ada.Synchronous_Task_Control 55 56 type Task_Body_Access is access procedure; 57 -- Pointer to the task body's entry point (or possibly a wrapper 58 -- declared local to the GNARL). 59 60 type Private_Data is limited private; 61 -- Any information that the GNULLI needs maintained on a per-task basis. 62 -- A component of this type is guaranteed to be included in the 63 -- Ada_Task_Control_Block. 64 65 subtype Task_Address is System.Address; 66 -- In some versions of Task_Primitives, notably for VMS, Task_Address is 67 -- the short version of address defined in System.Aux_DEC. To avoid 68 -- dragging Aux_DEC into tasking packages a tasking specific subtype is 69 -- defined here. 70 71 Task_Address_Size : constant := Standard'Address_Size; 72 -- The size of Task_Address 73 74 Alternate_Stack_Size : constant := 0; 75 -- No alternate signal stack is used on this platform 76 77private 78 type Lock is record 79 L : aliased System.OS_Interface.pthread_mutex_t; 80 Priority : Integer; 81 Owner_Priority : Integer; 82 end record; 83 84 type RTS_Lock is new System.OS_Interface.pthread_mutex_t; 85 86 type Suspension_Object is record 87 State : Boolean; 88 pragma Atomic (State); 89 -- Boolean that indicates whether the object is open. This field is 90 -- marked Atomic to ensure that we can read its value without locking 91 -- the access to the Suspension_Object. 92 93 Waiting : Boolean; 94 -- Flag showing if there is a task already suspended on this object 95 96 L : aliased System.OS_Interface.pthread_mutex_t; 97 -- Protection for ensuring mutual exclusion on the Suspension_Object 98 99 CV : aliased System.OS_Interface.pthread_cond_t; 100 -- Condition variable used to queue threads until condition is signaled 101 end record; 102 103 type Private_Data is record 104 Thread : aliased System.OS_Interface.pthread_t; 105 -- pragma Atomic (Thread); 106 -- Unfortunately, the above fails because Thread is 64 bits. 107 108 -- Thread field may be updated by two different threads of control. 109 -- (See, Enter_Task and Create_Task in s-taprop.adb). They put the 110 -- same value (thr_self value). We do not want to use lock on those 111 -- operations and the only thing we have to make sure is that they 112 -- are updated in atomic fashion. 113 114 CV : aliased System.OS_Interface.pthread_cond_t; 115 116 L : aliased RTS_Lock; 117 -- Protection for all components is lock L 118 end record; 119 120end System.Task_Primitives; 121