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 34 35-- Note: this file can only be used for POSIX compliant systems 36 37pragma Polling (Off); 38-- Turn off polling, we do not want ATC polling to take place during tasking 39-- operations. It causes infinite loops and other problems. 40 41with System.OS_Interface; 42 43package System.Task_Primitives is 44 pragma Preelaborate; 45 46 type Lock is limited private; 47 -- Should be used for implementation of protected objects 48 49 type RTS_Lock is limited private; 50 -- Should be used inside the runtime system. The difference between Lock 51 -- and the RTS_Lock is that the later one serves only as a semaphore so 52 -- that do not check for ceiling violations. 53 54 type Suspension_Object is limited private; 55 -- Should be used for the implementation of Ada.Synchronous_Task_Control 56 57 type Task_Body_Access is access procedure; 58 -- Pointer to the task body's entry point (or possibly a wrapper declared 59 -- local to the GNARL). 60 61 type Private_Data is limited private; 62 -- Any information that the GNULLI needs maintained on a per-task basis. 63 -- A component of this type is guaranteed to be included in the 64 -- Ada_Task_Control_Block. 65 66 subtype Task_Address is System.Address; 67 -- In some versions of Task_Primitives, notably for VMS, Task_Address is 68 -- the short version of address defined in System.Aux_DEC. To avoid 69 -- dragging Aux_DEC into tasking packages a tasking specific subtype is 70 -- defined here. 71 72 Task_Address_Size : constant := Standard'Address_Size; 73 -- The size of Task_Address 74 75 Alternate_Stack_Size : constant := System.OS_Interface.Alternate_Stack_Size; 76 -- Import value from System.OS_Interface 77 78private 79 80 type Lock is record 81 RW : aliased System.OS_Interface.pthread_rwlock_t; 82 WO : aliased System.OS_Interface.pthread_mutex_t; 83 end record; 84 85 type RTS_Lock is new System.OS_Interface.pthread_mutex_t; 86 87 type Suspension_Object is record 88 State : Boolean; 89 pragma Atomic (State); 90 -- Boolean that indicates whether the object is open. This field is 91 -- marked Atomic to ensure that we can read its value without locking 92 -- the access to the Suspension_Object. 93 94 Waiting : Boolean; 95 -- Flag showing if there is a task already suspended on this object 96 97 L : aliased System.OS_Interface.pthread_mutex_t; 98 -- Protection for ensuring mutual exclusion on the Suspension_Object 99 100 CV : aliased System.OS_Interface.pthread_cond_t; 101 -- Condition variable used to queue threads until condition is signaled 102 end record; 103 104 type Private_Data is record 105 Thread : aliased System.OS_Interface.pthread_t; 106 pragma Atomic (Thread); 107 -- Thread field may be updated by two different threads of control. 108 -- (See, Enter_Task and Create_Task in s-taprop.adb). They put the same 109 -- value (thr_self value). We do not want to use lock on those 110 -- operations and the only thing we have to make sure is that they are 111 -- updated in atomic fashion. 112 113 LWP : aliased System.Address; 114 -- The purpose of this field is to provide a better tasking support on 115 -- gdb. The order of the two first fields (Thread and LWP) is important. 116 -- On targets where lwp is not relevant, this is equivalent to Thread. 117 118 CV : aliased System.OS_Interface.pthread_cond_t; 119 -- Should be commented ??? (in all versions of taspri) 120 121 L : aliased RTS_Lock; 122 -- Protection for all components is lock L 123 end record; 124 125end System.Task_Primitives; 126