1 ------------------------------------------------------------------------------
3 -- GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS --
5 -- 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 --
10 -- Copyright (C) 1992-2001, Free Software Foundation, Inc. --
12 -- GNARL 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 2, or (at your option) any later ver- --
15 -- sion. GNARL 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. See the GNU General Public License --
18 -- for more details. You should have received a copy of the GNU General --
19 -- Public License distributed with GNARL; see file COPYING. If not, write --
20 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
21 -- MA 02111-1307, USA. --
23 -- As a special exception, if other files instantiate generics from this --
24 -- unit, or you link this unit with other files to produce an executable, --
25 -- this unit does not by itself cause the resulting executable to be --
26 -- covered by the GNU General Public License. This exception does not --
27 -- however invalidate any other reasons why the executable file might be --
28 -- covered by the GNU Public License. --
30 -- GNARL was developed by the GNARL team at Florida State University. --
31 -- Extensive contributions were provided by Ada Core Technologies, Inc. --
33 ------------------------------------------------------------------------------
35 -- This is a IRIX (pthread library) version of this package.
37 -- This package contains all the GNULL primitives that interface directly
38 -- with the underlying OS.
41 -- Turn off polling, we do not want ATC polling to take place during
42 -- tasking operations. It causes infinite loops and other problems.
48 with System.Task_Info;
50 with System.Tasking.Debug;
51 -- used for Known_Tasks
56 with System.Interrupt_Management;
57 -- used for Keep_Unmasked
58 -- Abort_Task_Interrupt
61 with System.Interrupt_Management.Operations;
62 -- used for Set_Interrupt_Mask
64 pragma Elaborate_All (System.Interrupt_Management.Operations);
66 with System.Parameters;
70 -- used for Ada_Task_Control_Block
73 with System.Soft_Links;
74 -- used for Defer/Undefer_Abort
76 -- Note that we do not use System.Tasking.Initialization directly since
77 -- this is a higher level package that we shouldn't depend on. For example
78 -- when using the restricted run time, it is replaced by
79 -- System.Tasking.Restricted.Initialization
81 with System.Program_Info;
82 -- used for Default_Task_Stack
85 -- Pthread_Sched_Signal
88 with System.OS_Interface;
89 -- used for various type, constant, and operations
91 with System.OS_Primitives;
92 -- used for Delay_Modes
94 with Unchecked_Conversion;
95 with Unchecked_Deallocation;
97 package body System.Task_Primitives.Operations is
100 use System.Tasking.Debug;
102 use System.OS_Interface;
103 use System.OS_Primitives;
104 use System.Parameters;
106 package SSL renames System.Soft_Links;
112 -- The followings are logically constants, but need to be initialized
115 ATCB_Key : aliased pthread_key_t;
116 -- Key used to find the Ada Task_ID associated with a thread
118 Single_RTS_Lock : aliased RTS_Lock;
119 -- This is a lock to allow only one thread of control in the RTS at
120 -- a time; it is used to execute in mutual exclusion from all other tasks.
121 -- Used mainly in Single_Lock mode, but also to protect All_Tasks_List
123 Environment_Task_ID : Task_ID;
124 -- A variable to hold Task_ID for the environment task.
126 Locking_Policy : Character;
127 pragma Import (C, Locking_Policy, "__gl_locking_policy");
129 Real_Time_Clock_Id : constant clockid_t := CLOCK_REALTIME;
131 Unblocked_Signal_Mask : aliased sigset_t;
133 -----------------------
134 -- Local Subprograms --
135 -----------------------
137 function To_Task_ID is new Unchecked_Conversion (System.Address, Task_ID);
139 function To_Address is new Unchecked_Conversion (Task_ID, System.Address);
141 procedure Abort_Handler (Sig : Signal);
147 procedure Abort_Handler (Sig : Signal) is
149 Result : Interfaces.C.int;
150 Old_Set : aliased sigset_t;
153 if T.Deferral_Level = 0
154 and then T.Pending_ATC_Level < T.ATC_Nesting_Level
156 -- Make sure signals used for RTS internal purpose are unmasked
158 Result := pthread_sigmask
160 Unblocked_Signal_Mask'Unchecked_Access,
161 Old_Set'Unchecked_Access);
162 pragma Assert (Result = 0);
164 raise Standard'Abort_Signal;
172 -- The underlying thread system sets a guard page at the
173 -- bottom of a thread stack, so nothing is needed.
175 procedure Stack_Guard (T : ST.Task_ID; On : Boolean) is
184 function Get_Thread_Id (T : ST.Task_ID) return OSI.Thread_Id is
186 return T.Common.LL.Thread;
193 function Self return Task_ID is
194 Result : System.Address;
197 Result := pthread_getspecific (ATCB_Key);
198 pragma Assert (Result /= System.Null_Address);
200 return To_Task_ID (Result);
203 ---------------------
204 -- Initialize_Lock --
205 ---------------------
207 -- Note: mutexes and cond_variables needed per-task basis are
208 -- initialized in Initialize_TCB and the Storage_Error is
209 -- handled. Other mutexes (such as RTS_Lock, Memory_Lock...)
210 -- used in RTS is initialized before any status change of RTS.
211 -- Therefore rasing Storage_Error in the following routines
212 -- should be able to be handled safely.
214 procedure Initialize_Lock
215 (Prio : System.Any_Priority;
218 Attributes : aliased pthread_mutexattr_t;
219 Result : Interfaces.C.int;
222 Result := pthread_mutexattr_init (Attributes'Access);
223 pragma Assert (Result = 0 or else Result = ENOMEM);
225 if Result = ENOMEM then
229 if Locking_Policy = 'C' then
230 Result := pthread_mutexattr_setprotocol
231 (Attributes'Access, PTHREAD_PRIO_PROTECT);
232 pragma Assert (Result = 0);
234 Result := pthread_mutexattr_setprioceiling
235 (Attributes'Access, Interfaces.C.int (Prio));
236 pragma Assert (Result = 0);
239 Result := pthread_mutex_init (L, Attributes'Access);
240 pragma Assert (Result = 0 or else Result = ENOMEM);
242 if Result = ENOMEM then
243 Result := pthread_mutexattr_destroy (Attributes'Access);
247 Result := pthread_mutexattr_destroy (Attributes'Access);
248 pragma Assert (Result = 0);
251 procedure Initialize_Lock (L : access RTS_Lock; Level : Lock_Level) is
252 Attributes : aliased pthread_mutexattr_t;
253 Result : Interfaces.C.int;
256 Result := pthread_mutexattr_init (Attributes'Access);
257 pragma Assert (Result = 0 or else Result = ENOMEM);
259 if Result = ENOMEM then
263 if Locking_Policy = 'C' then
264 Result := pthread_mutexattr_setprotocol
265 (Attributes'Access, PTHREAD_PRIO_PROTECT);
266 pragma Assert (Result = 0);
268 Result := pthread_mutexattr_setprioceiling
269 (Attributes'Access, Interfaces.C.int (System.Any_Priority'Last));
270 pragma Assert (Result = 0);
273 Result := pthread_mutex_init (L, Attributes'Access);
275 pragma Assert (Result = 0 or else Result = ENOMEM);
277 if Result = ENOMEM then
278 Result := pthread_mutexattr_destroy (Attributes'Access);
282 Result := pthread_mutexattr_destroy (Attributes'Access);
289 procedure Finalize_Lock (L : access Lock) is
290 Result : Interfaces.C.int;
293 Result := pthread_mutex_destroy (L);
294 pragma Assert (Result = 0);
297 procedure Finalize_Lock (L : access RTS_Lock) is
298 Result : Interfaces.C.int;
301 Result := pthread_mutex_destroy (L);
302 pragma Assert (Result = 0);
309 procedure Write_Lock (L : access Lock; Ceiling_Violation : out Boolean) is
310 Result : Interfaces.C.int;
312 Result := pthread_mutex_lock (L);
313 Ceiling_Violation := Result = EINVAL;
315 -- assumes the cause of EINVAL is a priority ceiling violation
317 pragma Assert (Result = 0 or else Result = EINVAL);
321 (L : access RTS_Lock; Global_Lock : Boolean := False)
323 Result : Interfaces.C.int;
325 if not Single_Lock or else Global_Lock then
326 Result := pthread_mutex_lock (L);
327 pragma Assert (Result = 0);
331 procedure Write_Lock (T : Task_ID) is
332 Result : Interfaces.C.int;
334 if not Single_Lock then
335 Result := pthread_mutex_lock (T.Common.LL.L'Access);
336 pragma Assert (Result = 0);
344 procedure Read_Lock (L : access Lock; Ceiling_Violation : out Boolean) is
346 Write_Lock (L, Ceiling_Violation);
353 procedure Unlock (L : access Lock) is
354 Result : Interfaces.C.int;
356 Result := pthread_mutex_unlock (L);
357 pragma Assert (Result = 0);
360 procedure Unlock (L : access RTS_Lock; Global_Lock : Boolean := False) is
361 Result : Interfaces.C.int;
363 if not Single_Lock or else Global_Lock then
364 Result := pthread_mutex_unlock (L);
365 pragma Assert (Result = 0);
369 procedure Unlock (T : Task_ID) is
370 Result : Interfaces.C.int;
372 if not Single_Lock then
373 Result := pthread_mutex_unlock (T.Common.LL.L'Access);
374 pragma Assert (Result = 0);
383 (Self_ID : ST.Task_ID;
384 Reason : System.Tasking.Task_States)
386 Result : Interfaces.C.int;
389 Result := pthread_cond_wait
390 (Self_ID.Common.LL.CV'Access, Single_RTS_Lock'Access);
392 Result := pthread_cond_wait
393 (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L'Access);
396 -- EINTR is not considered a failure.
398 pragma Assert (Result = 0 or else Result = EINTR);
405 procedure Timed_Sleep
408 Mode : ST.Delay_Modes;
409 Reason : Task_States;
410 Timedout : out Boolean;
411 Yielded : out Boolean)
413 Check_Time : constant Duration := Monotonic_Clock;
415 Request : aliased timespec;
416 Result : Interfaces.C.int;
422 if Mode = Relative then
423 Abs_Time := Duration'Min (Time, Max_Sensible_Delay) + Check_Time;
425 Abs_Time := Duration'Min (Check_Time + Max_Sensible_Delay, Time);
428 if Abs_Time > Check_Time then
429 Request := To_Timespec (Abs_Time);
432 exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level
433 or else Self_ID.Pending_Priority_Change;
436 Result := pthread_cond_timedwait
437 (Self_ID.Common.LL.CV'Access, Single_RTS_Lock'Access,
441 Result := pthread_cond_timedwait
442 (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L'Access,
446 exit when Abs_Time <= Monotonic_Clock;
448 if Result = 0 or else errno = EINTR then
460 -- This is for use in implementing delay statements, so
461 -- we assume the caller is abort-deferred but is holding
464 procedure Timed_Delay
467 Mode : ST.Delay_Modes)
469 Check_Time : constant Duration := Monotonic_Clock;
471 Request : aliased timespec;
472 Result : Interfaces.C.int;
475 -- Only the little window between deferring abort and
476 -- locking Self_ID is the reason we need to
477 -- check for pending abort and priority change below! :(
485 Write_Lock (Self_ID);
487 if Mode = Relative then
488 Abs_Time := Time + Check_Time;
490 Abs_Time := Duration'Min (Check_Time + Max_Sensible_Delay, Time);
493 if Abs_Time > Check_Time then
494 Request := To_Timespec (Abs_Time);
495 Self_ID.Common.State := Delay_Sleep;
498 if Self_ID.Pending_Priority_Change then
499 Self_ID.Pending_Priority_Change := False;
500 Self_ID.Common.Base_Priority := Self_ID.New_Base_Priority;
501 Set_Priority (Self_ID, Self_ID.Common.Base_Priority);
504 exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level;
506 Result := pthread_cond_timedwait (Self_ID.Common.LL.CV'Access,
507 Self_ID.Common.LL.L'Access, Request'Access);
508 exit when Abs_Time <= Monotonic_Clock;
510 pragma Assert (Result = 0
511 or else Result = ETIMEDOUT
512 or else Result = EINTR);
515 Self_ID.Common.State := Runnable;
525 SSL.Abort_Undefer.all;
528 ---------------------
529 -- Monotonic_Clock --
530 ---------------------
532 function Monotonic_Clock return Duration is
533 TS : aliased timespec;
534 Result : Interfaces.C.int;
537 Result := clock_gettime (Real_Time_Clock_Id, TS'Unchecked_Access);
538 pragma Assert (Result = 0);
539 return To_Duration (TS);
546 function RT_Resolution return Duration is
548 -- The clock_getres (Real_Time_Clock_Id) function appears to return
549 -- the interrupt resolution of the realtime clock and not the actual
550 -- resolution of reading the clock. Even though this last value is
551 -- only guaranteed to be 100 Hz, at least the Origin 200 appears to
552 -- have a microsecond resolution or better.
553 -- ??? We should figure out a method to return the right value on
556 return 0.000_001; -- Assume microsecond resolution of clock
563 procedure Wakeup (T : ST.Task_ID; Reason : System.Tasking.Task_States) is
564 Result : Interfaces.C.int;
566 Result := pthread_cond_signal (T.Common.LL.CV'Access);
567 pragma Assert (Result = 0);
574 procedure Yield (Do_Yield : Boolean := True) is
575 Result : Interfaces.C.int;
578 Result := sched_yield;
586 procedure Set_Priority
588 Prio : System.Any_Priority;
589 Loss_Of_Inheritance : Boolean := False)
591 Result : Interfaces.C.int;
592 Param : aliased struct_sched_param;
593 Sched_Policy : Interfaces.C.int;
595 use type System.Task_Info.Task_Info_Type;
597 function To_Int is new Unchecked_Conversion
598 (System.Task_Info.Thread_Scheduling_Policy, Interfaces.C.int);
601 T.Common.Current_Priority := Prio;
602 Param.sched_priority := Interfaces.C.int (Prio);
604 if T.Common.Task_Info /= null then
605 Sched_Policy := To_Int (T.Common.Task_Info.Policy);
607 Sched_Policy := SCHED_FIFO;
610 Result := pthread_setschedparam (T.Common.LL.Thread, Sched_Policy,
612 pragma Assert (Result = 0);
619 function Get_Priority (T : Task_ID) return System.Any_Priority is
621 return T.Common.Current_Priority;
628 procedure Enter_Task (Self_ID : Task_ID) is
629 Result : Interfaces.C.int;
631 function To_Int is new Unchecked_Conversion
632 (System.Task_Info.CPU_Number, Interfaces.C.int);
634 use System.Task_Info;
637 Self_ID.Common.LL.Thread := pthread_self;
638 Result := pthread_setspecific (ATCB_Key, To_Address (Self_ID));
639 pragma Assert (Result = 0);
641 if Self_ID.Common.Task_Info /= null
642 and then Self_ID.Common.Task_Info.Scope = PTHREAD_SCOPE_SYSTEM
643 and then Self_ID.Common.Task_Info.Runon_CPU /= ANY_CPU
645 Result := pthread_setrunon_np
646 (To_Int (Self_ID.Common.Task_Info.Runon_CPU));
647 pragma Assert (Result = 0);
652 for J in Known_Tasks'Range loop
653 if Known_Tasks (J) = null then
654 Known_Tasks (J) := Self_ID;
655 Self_ID.Known_Tasks_Index := J;
667 function New_ATCB (Entry_Num : Task_Entry_Index) return Task_ID is
669 return new Ada_Task_Control_Block (Entry_Num);
676 procedure Initialize_TCB (Self_ID : Task_ID; Succeeded : out Boolean) is
677 Result : Interfaces.C.int;
678 Cond_Attr : aliased pthread_condattr_t;
681 if not Single_Lock then
682 Initialize_Lock (Self_ID.Common.LL.L'Access, ATCB_Level);
685 Result := pthread_condattr_init (Cond_Attr'Access);
686 pragma Assert (Result = 0 or else Result = ENOMEM);
689 Result := pthread_cond_init (Self_ID.Common.LL.CV'Access,
691 pragma Assert (Result = 0 or else Result = ENOMEM);
697 if not Single_Lock then
698 Result := pthread_mutex_destroy (Self_ID.Common.LL.L'Access);
699 pragma Assert (Result = 0);
705 Result := pthread_condattr_destroy (Cond_Attr'Access);
706 pragma Assert (Result = 0);
713 procedure Create_Task
715 Wrapper : System.Address;
716 Stack_Size : System.Parameters.Size_Type;
717 Priority : System.Any_Priority;
718 Succeeded : out Boolean)
720 use System.Task_Info;
722 Attributes : aliased pthread_attr_t;
723 Sched_Param : aliased struct_sched_param;
724 Adjusted_Stack_Size : Interfaces.C.size_t;
725 Result : Interfaces.C.int;
727 function Thread_Body_Access is new
728 Unchecked_Conversion (System.Address, Thread_Body);
730 function To_Int is new Unchecked_Conversion
731 (System.Task_Info.Thread_Scheduling_Scope, Interfaces.C.int);
732 function To_Int is new Unchecked_Conversion
733 (System.Task_Info.Thread_Scheduling_Inheritance, Interfaces.C.int);
734 function To_Int is new Unchecked_Conversion
735 (System.Task_Info.Thread_Scheduling_Policy, Interfaces.C.int);
738 if Stack_Size = System.Parameters.Unspecified_Size then
739 Adjusted_Stack_Size :=
740 Interfaces.C.size_t (System.Program_Info.Default_Task_Stack);
742 elsif Stack_Size < Size_Type (Minimum_Stack_Size) then
743 Adjusted_Stack_Size :=
744 Interfaces.C.size_t (Minimum_Stack_Size);
747 Adjusted_Stack_Size := Interfaces.C.size_t (Stack_Size);
750 Result := pthread_attr_init (Attributes'Access);
751 pragma Assert (Result = 0 or else Result = ENOMEM);
758 Result := pthread_attr_setdetachstate
759 (Attributes'Access, PTHREAD_CREATE_DETACHED);
760 pragma Assert (Result = 0);
762 Result := pthread_attr_setstacksize
763 (Attributes'Access, Interfaces.C.size_t (Adjusted_Stack_Size));
764 pragma Assert (Result = 0);
766 if T.Common.Task_Info /= null then
767 Result := pthread_attr_setscope
768 (Attributes'Access, To_Int (T.Common.Task_Info.Scope));
769 pragma Assert (Result = 0);
771 Result := pthread_attr_setinheritsched
772 (Attributes'Access, To_Int (T.Common.Task_Info.Inheritance));
773 pragma Assert (Result = 0);
775 Result := pthread_attr_setschedpolicy
776 (Attributes'Access, To_Int (T.Common.Task_Info.Policy));
777 pragma Assert (Result = 0);
779 Sched_Param.sched_priority :=
780 Interfaces.C.int (T.Common.Task_Info.Priority);
782 Result := pthread_attr_setschedparam
783 (Attributes'Access, Sched_Param'Access);
784 pragma Assert (Result = 0);
787 -- Since the initial signal mask of a thread is inherited from the
788 -- creator, and the Environment task has all its signals masked, we
789 -- do not need to manipulate caller's signal mask at this point.
790 -- All tasks in RTS will have All_Tasks_Mask initially.
792 Result := pthread_create
793 (T.Common.LL.Thread'Access,
795 Thread_Body_Access (Wrapper),
799 and then T.Common.Task_Info /= null
800 and then T.Common.Task_Info.Scope = PTHREAD_SCOPE_SYSTEM
802 -- The pthread_create call may have failed because we
803 -- asked for a system scope pthread and none were
804 -- available (probably because the program was not executed
805 -- by the superuser). Let's try for a process scope pthread
806 -- instead of raising Tasking_Error.
809 ("Request for PTHREAD_SCOPE_SYSTEM in Task_Info pragma for task");
810 System.IO.Put ("""");
811 System.IO.Put (T.Common.Task_Image.all);
812 System.IO.Put_Line (""" could not be honored. ");
813 System.IO.Put_Line ("Scope changed to PTHREAD_SCOPE_PROCESS");
815 T.Common.Task_Info.Scope := PTHREAD_SCOPE_PROCESS;
816 Result := pthread_attr_setscope
817 (Attributes'Access, To_Int (T.Common.Task_Info.Scope));
818 pragma Assert (Result = 0);
820 Result := pthread_create
821 (T.Common.LL.Thread'Access,
823 Thread_Body_Access (Wrapper),
827 pragma Assert (Result = 0 or else Result = EAGAIN);
829 Succeeded := Result = 0;
831 Set_Priority (T, Priority);
833 Result := pthread_attr_destroy (Attributes'Access);
834 pragma Assert (Result = 0);
841 procedure Finalize_TCB (T : Task_ID) is
842 Result : Interfaces.C.int;
845 procedure Free is new
846 Unchecked_Deallocation (Ada_Task_Control_Block, Task_ID);
849 if not Single_Lock then
850 Result := pthread_mutex_destroy (T.Common.LL.L'Access);
851 pragma Assert (Result = 0);
854 Result := pthread_cond_destroy (T.Common.LL.CV'Access);
855 pragma Assert (Result = 0);
857 if T.Known_Tasks_Index /= -1 then
858 Known_Tasks (T.Known_Tasks_Index) := null;
868 procedure Exit_Task is
870 pthread_exit (System.Null_Address);
877 procedure Abort_Task (T : Task_ID) is
878 Result : Interfaces.C.int;
880 Result := pthread_kill (T.Common.LL.Thread,
881 Signal (System.Interrupt_Management.Abort_Task_Interrupt));
882 pragma Assert (Result = 0);
889 -- Dummy versions. The only currently working versions is for solaris
892 function Check_Exit (Self_ID : ST.Task_ID) return Boolean is
901 function Check_No_Locks (Self_ID : ST.Task_ID) return Boolean is
906 ----------------------
907 -- Environment_Task --
908 ----------------------
910 function Environment_Task return Task_ID is
912 return Environment_Task_ID;
913 end Environment_Task;
919 procedure Lock_RTS is
921 Write_Lock (Single_RTS_Lock'Access, Global_Lock => True);
928 procedure Unlock_RTS is
930 Unlock (Single_RTS_Lock'Access, Global_Lock => True);
937 function Suspend_Task
939 Thread_Self : Thread_Id) return Boolean is
950 Thread_Self : Thread_Id) return Boolean is
959 procedure Initialize (Environment_Task : Task_ID) is
960 act : aliased struct_sigaction;
961 old_act : aliased struct_sigaction;
962 Tmp_Set : aliased sigset_t;
963 Result : Interfaces.C.int;
966 Environment_Task_ID := Environment_Task;
968 -- Initialize the lock used to synchronize chain of all ATCBs.
969 Initialize_Lock (Single_RTS_Lock'Access, RTS_Lock_Level);
971 Enter_Task (Environment_Task);
973 -- Install the abort-signal handler
976 act.sa_handler := Abort_Handler'Address;
978 Result := sigemptyset (Tmp_Set'Access);
979 pragma Assert (Result = 0);
980 act.sa_mask := Tmp_Set;
984 Signal (System.Interrupt_Management.Abort_Task_Interrupt),
985 act'Unchecked_Access,
986 old_act'Unchecked_Access);
987 pragma Assert (Result = 0);
992 Result : Interfaces.C.int;
994 -- Mask Environment task for all signals. The original mask of the
995 -- Environment task will be recovered by Interrupt_Server task
996 -- during the elaboration of s-interr.adb.
998 System.Interrupt_Management.Operations.Set_Interrupt_Mask
999 (System.Interrupt_Management.Operations.All_Tasks_Mask'Access);
1001 -- Prepare the set of signals that should unblocked in all tasks
1003 Result := sigemptyset (Unblocked_Signal_Mask'Access);
1004 pragma Assert (Result = 0);
1006 for J in Interrupt_Management.Interrupt_ID loop
1007 if System.Interrupt_Management.Keep_Unmasked (J) then
1008 Result := sigaddset (Unblocked_Signal_Mask'Access, Signal (J));
1009 pragma Assert (Result = 0);
1013 Result := pthread_key_create (ATCB_Key'Access, null);
1014 pragma Assert (Result = 0);
1016 -- Pick the highest resolution Clock for Clock_Realtime
1017 -- ??? This code currently doesn't work (see c94007[ab] for example)
1019 -- if syssgi (SGI_CYCLECNTR_SIZE) = 64 then
1020 -- Real_Time_Clock_Id := CLOCK_SGI_CYCLE;
1022 -- Real_Time_Clock_Id := CLOCK_REALTIME;
1025 end System.Task_Primitives.Operations;