------------------------------------------------------------------------------ -- -- -- GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS -- -- -- -- S Y S T E M . T A S K _ P R I M I T I V E S . O P E R A T I O N S -- -- -- -- B o d y -- -- -- -- -- -- Copyright (C) 1992-2002, Free Software Foundation, Inc. -- -- -- -- GNARL is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- -- ware Foundation; either version 2, or (at your option) any later ver- -- -- sion. GNARL is distributed in the hope that it will be useful, but WITH- -- -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- -- for more details. You should have received a copy of the GNU General -- -- Public License distributed with GNARL; see file COPYING. If not, write -- -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, -- -- MA 02111-1307, USA. -- -- -- -- As a special exception, if other files instantiate generics from this -- -- unit, or you link this unit with other files to produce an executable, -- -- this unit does not by itself cause the resulting executable to be -- -- covered by the GNU General Public License. This exception does not -- -- however invalidate any other reasons why the executable file might be -- -- covered by the GNU Public License. -- -- -- -- GNARL was developed by the GNARL team at Florida State University. -- -- Extensive contributions were provided by Ada Core Technologies, Inc. -- -- -- ------------------------------------------------------------------------------ -- This is the VxWorks version of this package -- This package contains all the GNULL primitives that interface directly -- with the underlying OS. pragma Polling (Off); -- Turn off polling, we do not want ATC polling to take place during -- tasking operations. It causes infinite loops and other problems. with System.Tasking.Debug; -- used for Known_Tasks with System.Interrupt_Management; -- used for Keep_Unmasked -- Abort_Task_Interrupt -- Interrupt_ID -- Initialize_Interrupts with System.Soft_Links; -- used for Defer/Undefer_Abort -- Note that we do not use System.Tasking.Initialization directly since -- this is a higher level package that we shouldn't depend on. For example -- when using the restricted run time, it is replaced by -- System.Tasking.Restricted.Initialization with System.OS_Interface; -- used for various type, constant, and operations with System.Parameters; -- used for Size_Type with System.Tasking; -- used for Ada_Task_Control_Block -- Task_ID -- ATCB components and types with System.Task_Info; -- used for Task_Image with Interfaces.C; with Unchecked_Conversion; with Unchecked_Deallocation; package body System.Task_Primitives.Operations is use System.Tasking.Debug; use System.Tasking; use System.Task_Info; use System.OS_Interface; use System.Parameters; use type Interfaces.C.int; package SSL renames System.Soft_Links; subtype int is System.OS_Interface.int; Relative : constant := 0; ---------------- -- Local Data -- ---------------- -- The followings are logically constants, but need to be initialized -- at run time. Current_Task : aliased Task_ID; pragma Export (Ada, Current_Task); -- Task specific value used to store the Ada Task_ID. Single_RTS_Lock : aliased RTS_Lock; -- This is a lock to allow only one thread of control in the RTS at -- a time; it is used to execute in mutual exclusion from all other tasks. -- Used mainly in Single_Lock mode, but also to protect All_Tasks_List Environment_Task_ID : Task_ID; -- A variable to hold Task_ID for the environment task. Unblocked_Signal_Mask : aliased sigset_t; -- The set of signals that should unblocked in all tasks -- The followings are internal configuration constants needed. Time_Slice_Val : Integer; pragma Import (C, Time_Slice_Val, "__gl_time_slice_val"); Locking_Policy : Character; pragma Import (C, Locking_Policy, "__gl_locking_policy"); Dispatching_Policy : Character; pragma Import (C, Dispatching_Policy, "__gl_task_dispatching_policy"); FIFO_Within_Priorities : constant Boolean := Dispatching_Policy = 'F'; -- Indicates whether FIFO_Within_Priorities is set. Mutex_Protocol : Priority_Type; ----------------------- -- Local Subprograms -- ----------------------- procedure Abort_Handler (signo : Signal); function To_Address is new Unchecked_Conversion (Task_ID, System.Address); ------------------- -- Abort_Handler -- ------------------- procedure Abort_Handler (signo : Signal) is Self_ID : constant Task_ID := Self; Result : int; Old_Set : aliased sigset_t; begin if Self_ID.Deferral_Level = 0 and then Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level and then not Self_ID.Aborting then Self_ID.Aborting := True; -- Make sure signals used for RTS internal purpose are unmasked Result := pthread_sigmask (SIG_UNBLOCK, Unblocked_Signal_Mask'Unchecked_Access, Old_Set'Unchecked_Access); pragma Assert (Result = 0); raise Standard'Abort_Signal; end if; end Abort_Handler; ----------------- -- Stack_Guard -- ----------------- procedure Stack_Guard (T : ST.Task_ID; On : Boolean) is begin -- Nothing needed. null; end Stack_Guard; ------------------- -- Get_Thread_Id -- ------------------- function Get_Thread_Id (T : ST.Task_ID) return OSI.Thread_Id is begin return T.Common.LL.Thread; end Get_Thread_Id; ---------- -- Self -- ---------- function Self return Task_ID is begin pragma Assert (Current_Task /= null); return Current_Task; end Self; ----------------------------- -- Install_Signal_Handlers -- ----------------------------- procedure Install_Signal_Handlers; -- Install the default signal handlers for the current task. procedure Install_Signal_Handlers is act : aliased struct_sigaction; old_act : aliased struct_sigaction; Tmp_Set : aliased sigset_t; Result : int; begin act.sa_flags := 0; act.sa_handler := Abort_Handler'Address; Result := sigemptyset (Tmp_Set'Access); pragma Assert (Result = 0); act.sa_mask := Tmp_Set; Result := sigaction (Signal (Interrupt_Management.Abort_Task_Interrupt), act'Unchecked_Access, old_act'Unchecked_Access); pragma Assert (Result = 0); Interrupt_Management.Initialize_Interrupts; end Install_Signal_Handlers; --------------------- -- Initialize_Lock -- --------------------- procedure Initialize_Lock (Prio : System.Any_Priority; L : access Lock) is begin L.Mutex := semMCreate (SEM_Q_PRIORITY + SEM_INVERSION_SAFE); L.Prio_Ceiling := int (Prio); L.Protocol := Mutex_Protocol; pragma Assert (L.Mutex /= 0); end Initialize_Lock; procedure Initialize_Lock (L : access RTS_Lock; Level : Lock_Level) is begin L.Mutex := semMCreate (SEM_Q_PRIORITY + SEM_INVERSION_SAFE); L.Prio_Ceiling := int (System.Any_Priority'Last); L.Protocol := Mutex_Protocol; pragma Assert (L.Mutex /= 0); end Initialize_Lock; ------------------- -- Finalize_Lock -- ------------------- procedure Finalize_Lock (L : access Lock) is Result : int; begin Result := semDelete (L.Mutex); pragma Assert (Result = 0); end Finalize_Lock; procedure Finalize_Lock (L : access RTS_Lock) is Result : int; begin Result := semDelete (L.Mutex); pragma Assert (Result = 0); end Finalize_Lock; ---------------- -- Write_Lock -- ---------------- procedure Write_Lock (L : access Lock; Ceiling_Violation : out Boolean) is Result : int; begin if L.Protocol = Prio_Protect and then int (Self.Common.Current_Priority) > L.Prio_Ceiling then Ceiling_Violation := True; return; else Ceiling_Violation := False; end if; Result := semTake (L.Mutex, WAIT_FOREVER); pragma Assert (Result = 0); end Write_Lock; procedure Write_Lock (L : access RTS_Lock; Global_Lock : Boolean := False) is Result : int; begin if not Single_Lock or else Global_Lock then Result := semTake (L.Mutex, WAIT_FOREVER); pragma Assert (Result = 0); end if; end Write_Lock; procedure Write_Lock (T : Task_ID) is Result : int; begin if not Single_Lock then Result := semTake (T.Common.LL.L.Mutex, WAIT_FOREVER); pragma Assert (Result = 0); end if; end Write_Lock; --------------- -- Read_Lock -- --------------- procedure Read_Lock (L : access Lock; Ceiling_Violation : out Boolean) is begin Write_Lock (L, Ceiling_Violation); end Read_Lock; ------------ -- Unlock -- ------------ procedure Unlock (L : access Lock) is Result : int; begin Result := semGive (L.Mutex); pragma Assert (Result = 0); end Unlock; procedure Unlock (L : access RTS_Lock; Global_Lock : Boolean := False) is Result : int; begin if not Single_Lock or else Global_Lock then Result := semGive (L.Mutex); pragma Assert (Result = 0); end if; end Unlock; procedure Unlock (T : Task_ID) is Result : int; begin if not Single_Lock then Result := semGive (T.Common.LL.L.Mutex); pragma Assert (Result = 0); end if; end Unlock; ----------- -- Sleep -- ----------- procedure Sleep (Self_ID : Task_ID; Reason : System.Tasking.Task_States) is Result : int; begin pragma Assert (Self_ID = Self); -- Disable task scheduling. Result := taskLock; -- Release the mutex before sleeping. if Single_Lock then Result := semGive (Single_RTS_Lock.Mutex); else Result := semGive (Self_ID.Common.LL.L.Mutex); end if; pragma Assert (Result = 0); -- Indicate that there is another thread waiting on the CV. Self_ID.Common.LL.CV.Waiting := Self_ID.Common.LL.CV.Waiting + 1; -- Perform a blocking operation to take the CV semaphore. -- Note that a blocking operation in VxWorks will reenable -- task scheduling. When we are no longer blocked and control -- is returned, task scheduling will again be disabled. Result := semTake (Self_ID.Common.LL.CV.Sem, WAIT_FOREVER); if Result /= 0 then Self_ID.Common.LL.CV.Waiting := Self_ID.Common.LL.CV.Waiting - 1; pragma Assert (False); end if; -- Take the mutex back. if Single_Lock then Result := semTake (Single_RTS_Lock.Mutex, WAIT_FOREVER); else Result := semTake (Self_ID.Common.LL.L.Mutex, WAIT_FOREVER); end if; pragma Assert (Result = 0); -- Reenable task scheduling. Result := taskUnlock; end Sleep; ----------------- -- Timed_Sleep -- ----------------- -- This is for use within the run-time system, so abort is -- assumed to be already deferred, and the caller should be -- holding its own ATCB lock. procedure Timed_Sleep (Self_ID : Task_ID; Time : Duration; Mode : ST.Delay_Modes; Reason : System.Tasking.Task_States; Timedout : out Boolean; Yielded : out Boolean) is Ticks : int; Result : int; begin Timedout := True; Yielded := True; if Mode = Relative then -- Systematically add one since the first tick will delay -- *at most* 1 / Rate_Duration seconds, so we need to add one to -- be on the safe side. Ticks := To_Clock_Ticks (Time) + 1; else Ticks := To_Clock_Ticks (Time - Monotonic_Clock); end if; if Ticks > 0 then -- Disable task scheduling. Result := taskLock; -- Release the mutex before sleeping. if Single_Lock then Result := semGive (Single_RTS_Lock.Mutex); else Result := semGive (Self_ID.Common.LL.L.Mutex); end if; pragma Assert (Result = 0); -- Indicate that there is another thread waiting on the CV. Self_ID.Common.LL.CV.Waiting := Self_ID.Common.LL.CV.Waiting + 1; -- Perform a blocking operation to take the CV semaphore. -- Note that a blocking operation in VxWorks will reenable -- task scheduling. When we are no longer blocked and control -- is returned, task scheduling will again be disabled. Result := semTake (Self_ID.Common.LL.CV.Sem, Ticks); if Result = 0 then -- Somebody may have called Wakeup for us Timedout := False; else Self_ID.Common.LL.CV.Waiting := Self_ID.Common.LL.CV.Waiting - 1; if errno /= S_objLib_OBJ_TIMEOUT then Timedout := False; end if; end if; -- Take the mutex back. if Single_Lock then Result := semTake (Single_RTS_Lock.Mutex, WAIT_FOREVER); else Result := semTake (Self_ID.Common.LL.L.Mutex, WAIT_FOREVER); end if; pragma Assert (Result = 0); -- Reenable task scheduling. Result := taskUnlock; else taskDelay (0); end if; end Timed_Sleep; ----------------- -- Timed_Delay -- ----------------- -- This is for use in implementing delay statements, so -- we assume the caller is holding no locks. procedure Timed_Delay (Self_ID : Task_ID; Time : Duration; Mode : ST.Delay_Modes) is Orig : constant Duration := Monotonic_Clock; Absolute : Duration; Ticks : int; Timedout : Boolean; Result : int; begin SSL.Abort_Defer.all; if Single_Lock then Result := semTake (Single_RTS_Lock.Mutex, WAIT_FOREVER); else Result := semTake (Self_ID.Common.LL.L.Mutex, WAIT_FOREVER); end if; pragma Assert (Result = 0); if Mode = Relative then Absolute := Orig + Time; Ticks := To_Clock_Ticks (Time); if Ticks > 0 then -- The first tick will delay anytime between 0 and -- 1 / sysClkRateGet seconds, so we need to add one to -- be on the safe side. Ticks := Ticks + 1; end if; else Absolute := Time; Ticks := To_Clock_Ticks (Time - Orig); end if; if Ticks > 0 then Self_ID.Common.State := Delay_Sleep; loop if Self_ID.Pending_Priority_Change then Self_ID.Pending_Priority_Change := False; Self_ID.Common.Base_Priority := Self_ID.New_Base_Priority; Set_Priority (Self_ID, Self_ID.Common.Base_Priority); end if; exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level; Timedout := False; Result := taskLock; if Single_Lock then Result := semGive (Single_RTS_Lock.Mutex); else Result := semGive (Self_ID.Common.LL.L.Mutex); end if; pragma Assert (Result = 0); -- Indicate that there is another thread waiting on the CV. Self_ID.Common.LL.CV.Waiting := Self_ID.Common.LL.CV.Waiting + 1; Result := semTake (Self_ID.Common.LL.CV.Sem, Ticks); if Result /= 0 then Self_ID.Common.LL.CV.Waiting := Self_ID.Common.LL.CV.Waiting - 1; if errno = S_objLib_OBJ_TIMEOUT then Timedout := True; else Ticks := To_Clock_Ticks (Absolute - Monotonic_Clock); end if; end if; if Single_Lock then Result := semTake (Single_RTS_Lock.Mutex, WAIT_FOREVER); else Result := semTake (Self_ID.Common.LL.L.Mutex, WAIT_FOREVER); end if; pragma Assert (Result = 0); -- Reenable task scheduling. Result := taskUnlock; exit when Timedout; end loop; Self_ID.Common.State := Runnable; else taskDelay (0); end if; if Single_Lock then Result := semGive (Single_RTS_Lock.Mutex); else Result := semGive (Self_ID.Common.LL.L.Mutex); end if; pragma Assert (Result = 0); SSL.Abort_Undefer.all; end Timed_Delay; --------------------- -- Monotonic_Clock -- --------------------- function Monotonic_Clock return Duration is TS : aliased timespec; Result : int; begin Result := clock_gettime (CLOCK_REALTIME, TS'Unchecked_Access); pragma Assert (Result = 0); return To_Duration (TS); end Monotonic_Clock; ------------------- -- RT_Resolution -- ------------------- function RT_Resolution return Duration is begin return 10#1.0#E-6; end RT_Resolution; ------------ -- Wakeup -- ------------ procedure Wakeup (T : Task_ID; Reason : System.Tasking.Task_States) is Result : int; begin -- Disable task scheduling. Result := taskLock; -- Iff someone is currently waiting on the condition variable -- then release the semaphore; we don't want to leave the -- semaphore in the full state because the next guy to do -- a condition wait operation would not block. if T.Common.LL.CV.Waiting > 0 then Result := semGive (T.Common.LL.CV.Sem); -- One less thread waiting on the CV. T.Common.LL.CV.Waiting := T.Common.LL.CV.Waiting - 1; pragma Assert (Result = 0); end if; -- Reenable task scheduling. Result := taskUnlock; end Wakeup; ----------- -- Yield -- ----------- procedure Yield (Do_Yield : Boolean := True) is Result : int; begin Result := taskDelay (0); end Yield; ------------------ -- Set_Priority -- ------------------ type Prio_Array_Type is array (System.Any_Priority) of Integer; pragma Atomic_Components (Prio_Array_Type); Prio_Array : Prio_Array_Type; -- Global array containing the id of the currently running task for -- each priority. -- -- Note: we assume that we are on a single processor with run-til-blocked -- scheduling. procedure Set_Priority (T : Task_ID; Prio : System.Any_Priority; Loss_Of_Inheritance : Boolean := False) is Array_Item : Integer; Result : int; begin Result := taskPrioritySet (T.Common.LL.Thread, To_VxWorks_Priority (int (Prio))); pragma Assert (Result = 0); if FIFO_Within_Priorities then -- Annex D requirement [RM D.2.2 par. 9]: -- If the task drops its priority due to the loss of inherited -- priority, it is added at the head of the ready queue for its -- new active priority. if Loss_Of_Inheritance and then Prio < T.Common.Current_Priority then Array_Item := Prio_Array (T.Common.Base_Priority) + 1; Prio_Array (T.Common.Base_Priority) := Array_Item; loop -- Let some processes a chance to arrive Yield; -- Then wait for our turn to proceed exit when Array_Item = Prio_Array (T.Common.Base_Priority) or else Prio_Array (T.Common.Base_Priority) = 1; end loop; Prio_Array (T.Common.Base_Priority) := Prio_Array (T.Common.Base_Priority) - 1; end if; end if; T.Common.Current_Priority := Prio; end Set_Priority; ------------------ -- Get_Priority -- ------------------ function Get_Priority (T : Task_ID) return System.Any_Priority is begin return T.Common.Current_Priority; end Get_Priority; ---------------- -- Enter_Task -- ---------------- procedure Enter_Task (Self_ID : Task_ID) is Result : int; procedure Init_Float; pragma Import (C, Init_Float, "__gnat_init_float"); -- Properly initializes the FPU for PPC/MIPS systems. begin Self_ID.Common.LL.Thread := taskIdSelf; Result := taskVarAdd (0, Current_Task'Address); Current_Task := Self_ID; Init_Float; -- Install the signal handlers. -- This is called for each task since there is no signal inheritance -- between VxWorks tasks. Install_Signal_Handlers; Lock_RTS; for J in Known_Tasks'Range loop if Known_Tasks (J) = null then Known_Tasks (J) := Self_ID; Self_ID.Known_Tasks_Index := J; exit; end if; end loop; Unlock_RTS; end Enter_Task; -------------- -- New_ATCB -- -------------- function New_ATCB (Entry_Num : Task_Entry_Index) return Task_ID is begin return new Ada_Task_Control_Block (Entry_Num); end New_ATCB; -------------------- -- Initialize_TCB -- -------------------- procedure Initialize_TCB (Self_ID : Task_ID; Succeeded : out Boolean) is begin Self_ID.Common.LL.CV.Sem := semBCreate (SEM_Q_PRIORITY, SEM_EMPTY); Self_ID.Common.LL.CV.Waiting := 0; Self_ID.Common.LL.Thread := 0; if Self_ID.Common.LL.CV.Sem = 0 then Succeeded := False; else Succeeded := True; if not Single_Lock then Initialize_Lock (Self_ID.Common.LL.L'Access, ATCB_Level); end if; end if; end Initialize_TCB; ----------------- -- Create_Task -- ----------------- procedure Create_Task (T : Task_ID; Wrapper : System.Address; Stack_Size : System.Parameters.Size_Type; Priority : System.Any_Priority; Succeeded : out Boolean) is use type System.Task_Info.Task_Image_Type; Adjusted_Stack_Size : size_t; begin if Stack_Size = Unspecified_Size then Adjusted_Stack_Size := size_t (Default_Stack_Size); elsif Stack_Size < Minimum_Stack_Size then Adjusted_Stack_Size := size_t (Minimum_Stack_Size); else Adjusted_Stack_Size := size_t (Stack_Size); end if; -- Ask for 4 extra bytes of stack space so that the ATCB -- pointer can be stored below the stack limit, plus extra -- space for the frame of Task_Wrapper. This is so the user -- gets the amount of stack requested exclusive of the needs -- of the runtime. -- -- We also have to allocate n more bytes for the task name -- storage and enough space for the Wind Task Control Block -- which is around 0x778 bytes. VxWorks also seems to carve out -- additional space, so use 2048 as a nice round number. -- We might want to increment to the nearest page size in -- case we ever support VxVMI. -- -- XXX - we should come back and visit this so we can -- set the task name to something appropriate. Adjusted_Stack_Size := Adjusted_Stack_Size + 2048; -- Since the initial signal mask of a thread is inherited from the -- creator, and the Environment task has all its signals masked, we -- do not need to manipulate caller's signal mask at this point. -- All tasks in RTS will have All_Tasks_Mask initially. if T.Common.Task_Image = null then T.Common.LL.Thread := taskSpawn (System.Null_Address, To_VxWorks_Priority (int (Priority)), VX_FP_TASK, Adjusted_Stack_Size, Wrapper, To_Address (T)); else declare Name : aliased String (1 .. T.Common.Task_Image'Length + 1); begin Name (1 .. Name'Last - 1) := T.Common.Task_Image.all; Name (Name'Last) := ASCII.NUL; T.Common.LL.Thread := taskSpawn (Name'Address, To_VxWorks_Priority (int (Priority)), VX_FP_TASK, Adjusted_Stack_Size, Wrapper, To_Address (T)); end; end if; if T.Common.LL.Thread = -1 then Succeeded := False; else Succeeded := True; end if; Task_Creation_Hook (T.Common.LL.Thread); Set_Priority (T, Priority); end Create_Task; ------------------ -- Finalize_TCB -- ------------------ procedure Finalize_TCB (T : Task_ID) is Result : int; Tmp : Task_ID := T; procedure Free is new Unchecked_Deallocation (Ada_Task_Control_Block, Task_ID); begin if Single_Lock then Result := semDelete (T.Common.LL.L.Mutex); pragma Assert (Result = 0); end if; T.Common.LL.Thread := 0; Result := semDelete (T.Common.LL.CV.Sem); pragma Assert (Result = 0); if T.Known_Tasks_Index /= -1 then Known_Tasks (T.Known_Tasks_Index) := null; end if; Free (Tmp); end Finalize_TCB; --------------- -- Exit_Task -- --------------- procedure Exit_Task is begin Task_Termination_Hook; taskDelete (0); end Exit_Task; ---------------- -- Abort_Task -- ---------------- procedure Abort_Task (T : Task_ID) is Result : int; begin Result := kill (T.Common.LL.Thread, Signal (Interrupt_Management.Abort_Task_Interrupt)); pragma Assert (Result = 0); end Abort_Task; ---------------- -- Check_Exit -- ---------------- -- Dummy versions. The only currently working version is for solaris -- (native). function Check_Exit (Self_ID : ST.Task_ID) return Boolean is begin return True; end Check_Exit; -------------------- -- Check_No_Locks -- -------------------- function Check_No_Locks (Self_ID : ST.Task_ID) return Boolean is begin return True; end Check_No_Locks; ---------------------- -- Environment_Task -- ---------------------- function Environment_Task return Task_ID is begin return Environment_Task_ID; end Environment_Task; -------------- -- Lock_RTS -- -------------- procedure Lock_RTS is begin Write_Lock (Single_RTS_Lock'Access, Global_Lock => True); end Lock_RTS; ---------------- -- Unlock_RTS -- ---------------- procedure Unlock_RTS is begin Unlock (Single_RTS_Lock'Access, Global_Lock => True); end Unlock_RTS; ------------------ -- Suspend_Task -- ------------------ function Suspend_Task (T : ST.Task_ID; Thread_Self : Thread_Id) return Boolean is begin if T.Common.LL.Thread /= 0 and then T.Common.LL.Thread /= Thread_Self then return taskSuspend (T.Common.LL.Thread) = 0; else return True; end if; end Suspend_Task; ----------------- -- Resume_Task -- ----------------- function Resume_Task (T : ST.Task_ID; Thread_Self : Thread_Id) return Boolean is begin if T.Common.LL.Thread /= 0 and then T.Common.LL.Thread /= Thread_Self then return taskResume (T.Common.LL.Thread) = 0; else return True; end if; end Resume_Task; ---------------- -- Initialize -- ---------------- procedure Initialize (Environment_Task : Task_ID) is begin Environment_Task_ID := Environment_Task; -- Initialize the lock used to synchronize chain of all ATCBs. Initialize_Lock (Single_RTS_Lock'Access, RTS_Lock_Level); Enter_Task (Environment_Task); end Initialize; begin declare Result : int; begin if Locking_Policy = 'C' then Mutex_Protocol := Prio_Protect; elsif Locking_Policy = 'I' then Mutex_Protocol := Prio_Inherit; else Mutex_Protocol := Prio_None; end if; if Time_Slice_Val > 0 then Result := kernelTimeSlice (To_Clock_Ticks (Duration (Time_Slice_Val) / Duration (1_000_000.0))); end if; Result := sigemptyset (Unblocked_Signal_Mask'Access); pragma Assert (Result = 0); end; end System.Task_Primitives.Operations;