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) 1991-1994, Florida State University -- 10-- Copyright (C) 1995-2011, AdaCore -- 11-- -- 12-- GNAT is free software; you can redistribute it and/or modify it under -- 13-- terms of the GNU General Public License as published by the Free Soft- -- 14-- ware Foundation; either version 3, or (at your option) any later ver- -- 15-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- 16-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- 17-- or FITNESS FOR A PARTICULAR PURPOSE. -- 18-- -- 19-- As a special exception under Section 7 of GPL version 3, you are granted -- 20-- additional permissions described in the GCC Runtime Library Exception, -- 21-- version 3.1, as published by the Free Software Foundation. -- 22-- -- 23-- You should have received a copy of the GNU General Public License and -- 24-- a copy of the GCC Runtime Library Exception along with this program; -- 25-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- 26-- <http://www.gnu.org/licenses/>. -- 27-- -- 28-- GNARL was developed by the GNARL team at Florida State University. -- 29-- Extensive contributions were provided by Ada Core Technologies, Inc. -- 30-- -- 31------------------------------------------------------------------------------ 32 33-- This is a POSIX-like version of this package where no alternate stack 34-- is needed for stack checking. 35 36-- Note: this file can only be used for POSIX compliant systems 37 38pragma Polling (Off); 39-- Turn off polling, we do not want ATC polling to take place during tasking 40-- operations. It causes infinite loops and other problems. 41 42with System.OS_Interface; 43 44package System.Task_Primitives is 45 pragma Preelaborate; 46 47 type Lock is limited private; 48 -- Should be used for implementation of protected objects 49 50 type RTS_Lock is limited private; 51 -- Should be used inside the runtime system. The difference between Lock 52 -- and the RTS_Lock is that the later one serves only as a semaphore so 53 -- that do not check for ceiling violations. 54 55 type Suspension_Object is limited private; 56 -- Should be used for the implementation of Ada.Synchronous_Task_Control 57 58 type Task_Body_Access is access procedure; 59 -- Pointer to the task body's entry point (or possibly a wrapper declared 60 -- local to the GNARL). 61 62 type Private_Data is limited private; 63 -- Any information that the GNULLI needs maintained on a per-task basis. 64 -- A component of this type is guaranteed to be included in the 65 -- Ada_Task_Control_Block. 66 67 subtype Task_Address is System.Address; 68 -- In some versions of Task_Primitives, notably for VMS, Task_Address is 69 -- the short version of address defined in System.Aux_DEC. To avoid 70 -- dragging Aux_DEC into tasking packages a tasking specific subtype is 71 -- defined here. 72 73 Task_Address_Size : constant := Standard'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 WO : aliased System.OS_Interface.pthread_mutex_t; 83 RW : aliased System.OS_Interface.pthread_rwlock_t; 84 end record; 85 86 type RTS_Lock is new System.OS_Interface.pthread_mutex_t; 87 88 type Suspension_Object is record 89 State : Boolean; 90 pragma Atomic (State); 91 -- Boolean that indicates whether the object is open. This field is 92 -- marked Atomic to ensure that we can read its value without locking 93 -- the access to the Suspension_Object. 94 95 Waiting : Boolean; 96 -- Flag showing if there is a task already suspended on this object 97 98 L : aliased System.OS_Interface.pthread_mutex_t; 99 -- Protection for ensuring mutual exclusion on the Suspension_Object 100 101 CV : aliased System.OS_Interface.pthread_cond_t; 102 -- Condition variable used to queue threads until condition is signaled 103 end record; 104 105 type Private_Data is record 106 Thread : aliased System.OS_Interface.pthread_t; 107 pragma Atomic (Thread); 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 same 110 -- 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 are 112 -- updated in atomic fashion. 113 114 LWP : aliased System.Address; 115 -- The purpose of this field is to provide a better tasking support on 116 -- gdb. The order of the two first fields (Thread and LWP) is important. 117 -- On targets where lwp is not relevant, this is equivalent to Thread. 118 119 CV : aliased System.OS_Interface.pthread_cond_t; 120 -- Should be commented ??? (in all versions of taspri) 121 122 L : aliased RTS_Lock; 123 -- Protection for all components is lock L 124 end record; 125 126end System.Task_Primitives; 127