1------------------------------------------------------------------------------
2--                                                                          --
3--                 GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS                 --
4--                                                                          --
5--                   S Y S T E M . O S _ I N T E R F A C E                  --
6--                                                                          --
7--                                  S p e c                                 --
8--                                                                          --
9--             Copyright (C) 1991-2017, Florida State University            --
10--          Copyright (C) 1995-2019, Free Software Foundation, Inc.         --
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 GNU/Linux version of this package
34
35--  This package encapsulates all direct interfaces to OS services
36--  that are needed by the tasking run-time (libgnarl).
37
38--  PLEASE DO NOT add any with-clauses to this package or remove the pragma
39--  Preelaborate. This package is designed to be a bottom-level (leaf) package.
40
41with Ada.Unchecked_Conversion;
42with Interfaces.C;
43with System.Linux;
44with System.OS_Constants;
45
46package System.OS_Interface is
47   pragma Preelaborate;
48
49   pragma Linker_Options ("-lpthread");
50   pragma Linker_Options ("-lrt");
51   --  Needed for clock_getres with glibc versions prior to 2.17
52
53   subtype int            is Interfaces.C.int;
54   subtype char           is Interfaces.C.char;
55   subtype short          is Interfaces.C.short;
56   subtype long           is Interfaces.C.long;
57   subtype unsigned       is Interfaces.C.unsigned;
58   subtype unsigned_short is Interfaces.C.unsigned_short;
59   subtype unsigned_long  is Interfaces.C.unsigned_long;
60   subtype unsigned_char  is Interfaces.C.unsigned_char;
61   subtype plain_char     is Interfaces.C.plain_char;
62   subtype size_t         is Interfaces.C.size_t;
63
64   -----------
65   -- Errno --
66   -----------
67
68   function errno return int;
69   pragma Import (C, errno, "__get_errno");
70
71   EAGAIN    : constant := System.Linux.EAGAIN;
72   EINTR     : constant := System.Linux.EINTR;
73   EINVAL    : constant := System.Linux.EINVAL;
74   ENOMEM    : constant := System.Linux.ENOMEM;
75   EPERM     : constant := System.Linux.EPERM;
76   ETIMEDOUT : constant := System.Linux.ETIMEDOUT;
77
78   -------------
79   -- Signals --
80   -------------
81
82   Max_Interrupt : constant := 63;
83   type Signal is new int range 0 .. Max_Interrupt;
84   for Signal'Size use int'Size;
85
86   SIGHUP     : constant := System.Linux.SIGHUP;
87   SIGINT     : constant := System.Linux.SIGINT;
88   SIGQUIT    : constant := System.Linux.SIGQUIT;
89   SIGILL     : constant := System.Linux.SIGILL;
90   SIGTRAP    : constant := System.Linux.SIGTRAP;
91   SIGIOT     : constant := System.Linux.SIGIOT;
92   SIGABRT    : constant := System.Linux.SIGABRT;
93   SIGBUS     : constant := System.Linux.SIGBUS;
94   SIGFPE     : constant := System.Linux.SIGFPE;
95   SIGKILL    : constant := System.Linux.SIGKILL;
96   SIGUSR1    : constant := System.Linux.SIGUSR1;
97   SIGSEGV    : constant := System.Linux.SIGSEGV;
98   SIGUSR2    : constant := System.Linux.SIGUSR2;
99   SIGPIPE    : constant := System.Linux.SIGPIPE;
100   SIGALRM    : constant := System.Linux.SIGALRM;
101   SIGTERM    : constant := System.Linux.SIGTERM;
102   SIGSTKFLT  : constant := System.Linux.SIGSTKFLT;
103   SIGCLD     : constant := System.Linux.SIGCLD;
104   SIGCHLD    : constant := System.Linux.SIGCHLD;
105   SIGCONT    : constant := System.Linux.SIGCONT;
106   SIGSTOP    : constant := System.Linux.SIGSTOP;
107   SIGTSTP    : constant := System.Linux.SIGTSTP;
108   SIGTTIN    : constant := System.Linux.SIGTTIN;
109   SIGTTOU    : constant := System.Linux.SIGTTOU;
110   SIGURG     : constant := System.Linux.SIGURG;
111   SIGXCPU    : constant := System.Linux.SIGXCPU;
112   SIGXFSZ    : constant := System.Linux.SIGXFSZ;
113   SIGVTALRM  : constant := System.Linux.SIGVTALRM;
114   SIGPROF    : constant := System.Linux.SIGPROF;
115   SIGWINCH   : constant := System.Linux.SIGWINCH;
116   SIGPOLL    : constant := System.Linux.SIGPOLL;
117   SIGIO      : constant := System.Linux.SIGIO;
118   SIGLOST    : constant := System.Linux.SIGLOST;
119   SIGPWR     : constant := System.Linux.SIGPWR;
120   SIGSYS     : constant := System.Linux.SIGSYS;
121   SIGUNUSED  : constant := System.Linux.SIGUNUSED;
122   SIG32      : constant := System.Linux.SIG32;
123   SIG33      : constant := System.Linux.SIG33;
124   SIG34      : constant := System.Linux.SIG34;
125
126   SIGADAABORT : constant := SIGABRT;
127   --  Change this to use another signal for task abort. SIGTERM might be a
128   --  good one.
129
130   type Signal_Set is array (Natural range <>) of Signal;
131
132   Unmasked : constant Signal_Set := (
133      SIGTRAP,
134      --  To enable debugging on multithreaded applications, mark SIGTRAP to
135      --  be kept unmasked.
136
137      SIGBUS,
138
139      SIGTTIN, SIGTTOU, SIGTSTP,
140      --  Keep these three signals unmasked so that background processes and IO
141      --  behaves as normal "C" applications
142
143      SIGPROF,
144      --  To avoid confusing the profiler
145
146      SIGKILL, SIGSTOP
147      --  These two signals actually can't be masked (POSIX won't allow it)
148      );
149
150   Reserved : constant Signal_Set := (
151      SIG32, SIG33, SIG34
152      --  glibc POSIX threads implementation uses two (NPTL) or three
153      --  (LinuxThreads) real-time signals for its own use (see SIGNAL(7)).
154      --  These signals are considered reserved and not unmasked as glibc does
155      --  not permit these signals to be used by the public signal.h API.
156      --  While LinuxThreads is mostly likely unused now, SIG34 is still
157      --  reserved as this behavior is consistent with past GNAT releases.
158      );
159
160   type sigset_t is private;
161
162   function sigaddset (set : access sigset_t; sig : Signal) return int;
163   pragma Import (C, sigaddset, "sigaddset");
164
165   function sigdelset (set : access sigset_t; sig : Signal) return int;
166   pragma Import (C, sigdelset, "sigdelset");
167
168   function sigfillset (set : access sigset_t) return int;
169   pragma Import (C, sigfillset, "sigfillset");
170
171   function sigismember (set : access sigset_t; sig : Signal) return int;
172   pragma Import (C, sigismember, "sigismember");
173
174   function sigemptyset (set : access sigset_t) return int;
175   pragma Import (C, sigemptyset, "sigemptyset");
176
177   type union_type_3 is new String (1 .. 116);
178   type siginfo_t is record
179      si_signo : int;
180      si_code  : int;
181      si_errno : int;
182      X_data   : union_type_3;
183   end record;
184   pragma Convention (C, siginfo_t);
185
186   type struct_sigaction is record
187      sa_handler  : System.Address;
188      sa_mask     : sigset_t;
189      sa_flags    : int;
190      sa_restorer : System.Address;
191   end record;
192   pragma Convention (C, struct_sigaction);
193
194   type struct_sigaction_ptr is access all struct_sigaction;
195
196   type Machine_State is record
197      eip : unsigned_long;
198      ebx : unsigned_long;
199      esp : unsigned_long;
200      ebp : unsigned_long;
201      esi : unsigned_long;
202      edi : unsigned_long;
203   end record;
204   type Machine_State_Ptr is access all Machine_State;
205
206   SA_SIGINFO : constant := System.Linux.SA_SIGINFO;
207   SA_ONSTACK : constant := System.Linux.SA_ONSTACK;
208
209   SIG_BLOCK   : constant := 0;
210   SIG_UNBLOCK : constant := 1;
211   SIG_SETMASK : constant := 2;
212
213   SIG_DFL : constant := 0;
214   SIG_IGN : constant := 1;
215
216   function sigaction
217     (sig  : Signal;
218      act  : struct_sigaction_ptr;
219      oact : struct_sigaction_ptr) return int;
220   pragma Import (C, sigaction, "sigaction");
221
222   ----------
223   -- Time --
224   ----------
225
226   subtype time_t    is System.Linux.time_t;
227   subtype timespec  is System.Linux.timespec;
228   subtype timeval   is System.Linux.timeval;
229   subtype clockid_t is System.Linux.clockid_t;
230
231   function clock_gettime
232     (clock_id : clockid_t; tp : access timespec) return int;
233   pragma Import (C, clock_gettime, "clock_gettime");
234
235   function clock_getres
236     (clock_id : clockid_t;
237      res      : access timespec) return int;
238   pragma Import (C, clock_getres, "clock_getres");
239
240   function To_Duration (TS : timespec) return Duration;
241   pragma Inline (To_Duration);
242
243   function To_Timespec (D : Duration) return timespec;
244   pragma Inline (To_Timespec);
245
246   function sysconf (name : int) return long;
247   pragma Import (C, sysconf);
248
249   SC_CLK_TCK          : constant := 2;
250   SC_NPROCESSORS_ONLN : constant := 84;
251
252   -------------------------
253   -- Priority Scheduling --
254   -------------------------
255
256   SCHED_OTHER : constant := 0;
257   SCHED_FIFO  : constant := 1;
258   SCHED_RR    : constant := 2;
259
260   function To_Target_Priority
261     (Prio : System.Any_Priority) return Interfaces.C.int;
262   --  Maps System.Any_Priority to a POSIX priority
263
264   -------------
265   -- Process --
266   -------------
267
268   type pid_t is private;
269
270   function kill (pid : pid_t; sig : Signal) return int;
271   pragma Import (C, kill, "kill");
272
273   function getpid return pid_t;
274   pragma Import (C, getpid, "getpid");
275
276   PR_SET_NAME : constant := 15;
277   PR_GET_NAME : constant := 16;
278
279   function prctl
280     (option                 : int;
281      arg2, arg3, arg4, arg5 : unsigned_long := 0) return int;
282   pragma Import (C, prctl);
283
284   -------------
285   -- Threads --
286   -------------
287
288   type Thread_Body is access
289     function (arg : System.Address) return System.Address;
290   pragma Convention (C, Thread_Body);
291
292   function Thread_Body_Access is new
293     Ada.Unchecked_Conversion (System.Address, Thread_Body);
294
295   type pthread_t is new unsigned_long;
296   subtype Thread_Id is pthread_t;
297
298   function To_pthread_t is
299     new Ada.Unchecked_Conversion (unsigned_long, pthread_t);
300
301   type pthread_mutex_t      is limited private;
302   type pthread_rwlock_t     is limited private;
303   type pthread_cond_t       is limited private;
304   type pthread_attr_t       is limited private;
305   type pthread_mutexattr_t  is limited private;
306   type pthread_rwlockattr_t is limited private;
307   type pthread_condattr_t   is limited private;
308   type pthread_key_t        is private;
309
310   PTHREAD_CREATE_DETACHED : constant := 1;
311
312   -----------
313   -- Stack --
314   -----------
315
316   type stack_t is record
317      ss_sp    : System.Address;
318      ss_flags : int;
319      ss_size  : size_t;
320   end record;
321   pragma Convention (C, stack_t);
322
323   function sigaltstack
324     (ss  : not null access stack_t;
325      oss : access stack_t) return int;
326   pragma Import (C, sigaltstack, "sigaltstack");
327
328   Alternate_Stack : aliased System.Address;
329   pragma Import (C, Alternate_Stack, "__gnat_alternate_stack");
330   --  The alternate signal stack for stack overflows
331
332   Alternate_Stack_Size : constant := 16 * 1024;
333   --  This must be in keeping with init.c:__gnat_alternate_stack
334
335   function Get_Stack_Base (thread : pthread_t) return Address;
336   pragma Inline (Get_Stack_Base);
337   --  This is a dummy procedure to share some GNULLI files
338
339   ---------------------------------------
340   -- Nonstandard Thread Initialization --
341   ---------------------------------------
342
343   procedure pthread_init;
344   pragma Inline (pthread_init);
345   --  This is a dummy procedure to share some GNULLI files
346
347   -------------------------
348   -- POSIX.1c  Section 3 --
349   -------------------------
350
351   function sigwait (set : access sigset_t; sig : access Signal) return int;
352   pragma Import (C, sigwait, "sigwait");
353
354   function pthread_kill (thread : pthread_t; sig : Signal) return int;
355   pragma Import (C, pthread_kill, "pthread_kill");
356
357   function pthread_sigmask
358     (how  : int;
359      set  : access sigset_t;
360      oset : access sigset_t) return int;
361   pragma Import (C, pthread_sigmask, "pthread_sigmask");
362
363   --------------------------
364   -- POSIX.1c  Section 11 --
365   --------------------------
366
367   function pthread_mutexattr_init
368     (attr : access pthread_mutexattr_t) return int;
369   pragma Import (C, pthread_mutexattr_init, "pthread_mutexattr_init");
370
371   function pthread_mutexattr_destroy
372     (attr : access pthread_mutexattr_t) return int;
373   pragma Import (C, pthread_mutexattr_destroy, "pthread_mutexattr_destroy");
374
375   function pthread_mutex_init
376     (mutex : access pthread_mutex_t;
377      attr  : access pthread_mutexattr_t) return int;
378   pragma Import (C, pthread_mutex_init, "pthread_mutex_init");
379
380   function pthread_mutex_destroy (mutex : access pthread_mutex_t) return int;
381   pragma Import (C, pthread_mutex_destroy, "pthread_mutex_destroy");
382
383   function pthread_mutex_lock (mutex : access pthread_mutex_t) return int;
384   pragma Import (C, pthread_mutex_lock, "pthread_mutex_lock");
385
386   function pthread_mutex_unlock (mutex : access pthread_mutex_t) return int;
387   pragma Import (C, pthread_mutex_unlock, "pthread_mutex_unlock");
388
389   function pthread_rwlockattr_init
390     (attr : access pthread_rwlockattr_t) return int;
391   pragma Import (C, pthread_rwlockattr_init, "pthread_rwlockattr_init");
392
393   function pthread_rwlockattr_destroy
394     (attr : access pthread_rwlockattr_t) return int;
395   pragma Import (C, pthread_rwlockattr_destroy, "pthread_rwlockattr_destroy");
396
397   PTHREAD_RWLOCK_PREFER_READER_NP              : constant := 0;
398   PTHREAD_RWLOCK_PREFER_WRITER_NP              : constant := 1;
399   PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP : constant := 2;
400
401   function pthread_rwlockattr_setkind_np
402     (attr : access pthread_rwlockattr_t;
403      pref : int) return int;
404   pragma Import
405     (C, pthread_rwlockattr_setkind_np, "pthread_rwlockattr_setkind_np");
406
407   function pthread_rwlock_init
408     (mutex : access pthread_rwlock_t;
409      attr  : access pthread_rwlockattr_t) return int;
410   pragma Import (C, pthread_rwlock_init, "pthread_rwlock_init");
411
412   function pthread_rwlock_destroy
413     (mutex : access pthread_rwlock_t) return int;
414   pragma Import (C, pthread_rwlock_destroy, "pthread_rwlock_destroy");
415
416   function pthread_rwlock_rdlock (mutex : access pthread_rwlock_t) return int;
417   pragma Import (C, pthread_rwlock_rdlock, "pthread_rwlock_rdlock");
418
419   function pthread_rwlock_wrlock (mutex : access pthread_rwlock_t) return int;
420   pragma Import (C, pthread_rwlock_wrlock, "pthread_rwlock_wrlock");
421
422   function pthread_rwlock_unlock (mutex : access pthread_rwlock_t) return int;
423   pragma Import (C, pthread_rwlock_unlock, "pthread_rwlock_unlock");
424
425   function pthread_condattr_init
426     (attr : access pthread_condattr_t) return int;
427   pragma Import (C, pthread_condattr_init, "pthread_condattr_init");
428
429   function pthread_condattr_destroy
430     (attr : access pthread_condattr_t) return int;
431   pragma Import (C, pthread_condattr_destroy, "pthread_condattr_destroy");
432
433   function pthread_cond_init
434     (cond : access pthread_cond_t;
435      attr : access pthread_condattr_t) return int;
436   pragma Import (C, pthread_cond_init, "pthread_cond_init");
437
438   function pthread_cond_destroy (cond : access pthread_cond_t) return int;
439   pragma Import (C, pthread_cond_destroy, "pthread_cond_destroy");
440
441   function pthread_cond_signal (cond : access pthread_cond_t) return int;
442   pragma Import (C, pthread_cond_signal, "pthread_cond_signal");
443
444   function pthread_cond_wait
445     (cond  : access pthread_cond_t;
446      mutex : access pthread_mutex_t) return int;
447   pragma Import (C, pthread_cond_wait, "pthread_cond_wait");
448
449   function pthread_cond_timedwait
450     (cond    : access pthread_cond_t;
451      mutex   : access pthread_mutex_t;
452      abstime : access timespec) return int;
453   pragma Import (C, pthread_cond_timedwait, "pthread_cond_timedwait");
454
455   --------------------------
456   -- POSIX.1c  Section 13 --
457   --------------------------
458
459   PTHREAD_PRIO_NONE    : constant := 0;
460   PTHREAD_PRIO_INHERIT : constant := 1;
461   PTHREAD_PRIO_PROTECT : constant := 2;
462
463   function pthread_mutexattr_setprotocol
464     (attr     : access pthread_mutexattr_t;
465      protocol : int) return int;
466   pragma Import (C, pthread_mutexattr_setprotocol);
467
468   function pthread_mutexattr_setprioceiling
469     (attr        : access pthread_mutexattr_t;
470      prioceiling : int) return int;
471   pragma Import (C, pthread_mutexattr_setprioceiling);
472
473   type struct_sched_param is record
474      sched_priority : int;  --  scheduling priority
475   end record;
476   pragma Convention (C, struct_sched_param);
477
478   function pthread_setschedparam
479     (thread : pthread_t;
480      policy : int;
481      param  : access struct_sched_param) return int;
482   pragma Import (C, pthread_setschedparam, "pthread_setschedparam");
483
484   function pthread_attr_setschedpolicy
485     (attr   : access pthread_attr_t;
486      policy : int) return int;
487   pragma Import
488     (C, pthread_attr_setschedpolicy, "pthread_attr_setschedpolicy");
489
490   function sched_yield return int;
491   pragma Import (C, sched_yield, "sched_yield");
492
493   ---------------------------
494   -- P1003.1c - Section 16 --
495   ---------------------------
496
497   function pthread_attr_init
498     (attributes : access pthread_attr_t) return int;
499   pragma Import (C, pthread_attr_init, "pthread_attr_init");
500
501   function pthread_attr_destroy
502     (attributes : access pthread_attr_t) return int;
503   pragma Import (C, pthread_attr_destroy, "pthread_attr_destroy");
504
505   function pthread_attr_setdetachstate
506     (attr        : access pthread_attr_t;
507      detachstate : int) return int;
508   pragma Import
509     (C, pthread_attr_setdetachstate, "pthread_attr_setdetachstate");
510
511   function pthread_attr_setstacksize
512     (attr      : access pthread_attr_t;
513      stacksize : size_t) return int;
514   pragma Import (C, pthread_attr_setstacksize, "pthread_attr_setstacksize");
515
516   function pthread_create
517     (thread        : access pthread_t;
518      attributes    : access pthread_attr_t;
519      start_routine : Thread_Body;
520      arg           : System.Address) return int;
521   pragma Import (C, pthread_create, "pthread_create");
522
523   procedure pthread_exit (status : System.Address);
524   pragma Import (C, pthread_exit, "pthread_exit");
525
526   function pthread_self return pthread_t;
527   pragma Import (C, pthread_self, "pthread_self");
528
529   function lwp_self return System.Address;
530   pragma Import (C, lwp_self, "__gnat_lwp_self");
531
532   --------------------------
533   -- POSIX.1c  Section 17 --
534   --------------------------
535
536   function pthread_setspecific
537     (key   : pthread_key_t;
538      value : System.Address) return int;
539   pragma Import (C, pthread_setspecific, "pthread_setspecific");
540
541   function pthread_getspecific (key : pthread_key_t) return System.Address;
542   pragma Import (C, pthread_getspecific, "pthread_getspecific");
543
544   type destructor_pointer is access procedure (arg : System.Address);
545   pragma Convention (C, destructor_pointer);
546
547   function pthread_key_create
548     (key        : access pthread_key_t;
549      destructor : destructor_pointer) return int;
550   pragma Import (C, pthread_key_create, "pthread_key_create");
551
552   ----------------
553   -- Extensions --
554   ----------------
555
556   CPU_SETSIZE : constant := 1_024;
557   --  Size of the cpu_set_t mask on most linux systems (SUSE 11 uses 4_096).
558   --  This is kept for backward compatibility (System.Task_Info uses it), but
559   --  the run-time library does no longer rely on static masks, using
560   --  dynamically allocated masks instead.
561
562   type bit_field is array (1 .. CPU_SETSIZE) of Boolean;
563   for bit_field'Size use CPU_SETSIZE;
564   pragma Pack (bit_field);
565   pragma Convention (C, bit_field);
566
567   type cpu_set_t is record
568      bits : bit_field;
569   end record;
570   pragma Convention (C, cpu_set_t);
571
572   type cpu_set_t_ptr is access all cpu_set_t;
573   --  In the run-time library we use this pointer because the size of type
574   --  cpu_set_t varies depending on the glibc version. Hence, objects of type
575   --  cpu_set_t are allocated dynamically using the number of processors
576   --  available in the target machine (value obtained at execution time).
577
578   function CPU_ALLOC (count : size_t) return cpu_set_t_ptr;
579   pragma Import (C, CPU_ALLOC, "__gnat_cpu_alloc");
580   --  Wrapper around the CPU_ALLOC C macro
581
582   function CPU_ALLOC_SIZE (count : size_t) return size_t;
583   pragma Import (C, CPU_ALLOC_SIZE, "__gnat_cpu_alloc_size");
584   --  Wrapper around the CPU_ALLOC_SIZE C macro
585
586   procedure CPU_FREE (cpuset : cpu_set_t_ptr);
587   pragma Import (C, CPU_FREE, "__gnat_cpu_free");
588   --  Wrapper around the CPU_FREE C macro
589
590   procedure CPU_ZERO (count : size_t; cpuset : cpu_set_t_ptr);
591   pragma Import (C, CPU_ZERO, "__gnat_cpu_zero");
592   --  Wrapper around the CPU_ZERO_S C macro
593
594   procedure CPU_SET (cpu : int; count : size_t; cpuset : cpu_set_t_ptr);
595   pragma Import (C, CPU_SET, "__gnat_cpu_set");
596   --  Wrapper around the CPU_SET_S C macro
597
598   function pthread_setaffinity_np
599     (thread     : pthread_t;
600      cpusetsize : size_t;
601      cpuset     : cpu_set_t_ptr) return int;
602   pragma Import (C, pthread_setaffinity_np, "pthread_setaffinity_np");
603   pragma Weak_External (pthread_setaffinity_np);
604   --  Use a weak symbol because this function may be available or not,
605   --  depending on the version of the system.
606
607   function pthread_attr_setaffinity_np
608     (attr       : access pthread_attr_t;
609      cpusetsize : size_t;
610      cpuset     : cpu_set_t_ptr) return int;
611   pragma Import (C, pthread_attr_setaffinity_np,
612                    "pthread_attr_setaffinity_np");
613   pragma Weak_External (pthread_attr_setaffinity_np);
614   --  Use a weak symbol because this function may be available or not,
615   --  depending on the version of the system.
616
617private
618
619   type sigset_t is
620     array (0 .. OS_Constants.SIZEOF_sigset - 1) of unsigned_char;
621   pragma Convention (C, sigset_t);
622   for sigset_t'Alignment use Interfaces.C.unsigned_long'Alignment;
623
624   pragma Warnings (Off);
625   for struct_sigaction use record
626      sa_handler at Linux.sa_handler_pos range 0 .. Standard'Address_Size - 1;
627      sa_mask    at Linux.sa_mask_pos    range 0 .. 1023;
628      sa_flags   at Linux.sa_flags_pos   range 0 .. int'Size - 1;
629   end record;
630   --  We intentionally leave sa_restorer unspecified and let the compiler
631   --  append it after the last field, so disable corresponding warning.
632   pragma Warnings (On);
633
634   type pid_t is new int;
635
636   subtype char_array is Interfaces.C.char_array;
637
638   type pthread_attr_t is record
639      Data : char_array (1 .. OS_Constants.PTHREAD_ATTR_SIZE);
640   end record;
641   pragma Convention (C, pthread_attr_t);
642   for pthread_attr_t'Alignment use Interfaces.C.unsigned_long'Alignment;
643
644   type pthread_condattr_t is record
645      Data : char_array (1 .. OS_Constants.PTHREAD_CONDATTR_SIZE);
646   end record;
647   pragma Convention (C, pthread_condattr_t);
648   for pthread_condattr_t'Alignment use Interfaces.C.int'Alignment;
649
650   type pthread_mutexattr_t is record
651      Data : char_array (1 .. OS_Constants.PTHREAD_MUTEXATTR_SIZE);
652   end  record;
653   pragma Convention (C, pthread_mutexattr_t);
654   for pthread_mutexattr_t'Alignment use Interfaces.C.int'Alignment;
655
656   type pthread_mutex_t is record
657      Data : char_array (1 .. OS_Constants.PTHREAD_MUTEX_SIZE);
658   end record;
659   pragma Convention (C, pthread_mutex_t);
660   for pthread_mutex_t'Alignment use Interfaces.C.unsigned_long'Alignment;
661
662   type pthread_rwlockattr_t is record
663      Data : char_array (1 .. OS_Constants.PTHREAD_RWLOCKATTR_SIZE);
664   end record;
665   pragma Convention (C, pthread_rwlockattr_t);
666   for pthread_rwlockattr_t'Alignment use Interfaces.C.unsigned_long'Alignment;
667
668   type pthread_rwlock_t is record
669      Data : char_array (1 .. OS_Constants.PTHREAD_RWLOCK_SIZE);
670   end record;
671   pragma Convention (C, pthread_rwlock_t);
672   for pthread_rwlock_t'Alignment use Interfaces.C.unsigned_long'Alignment;
673
674   type pthread_cond_t is record
675      Data : char_array (1 .. OS_Constants.PTHREAD_COND_SIZE);
676   end record;
677   pragma Convention (C, pthread_cond_t);
678   for pthread_cond_t'Alignment use Interfaces.Unsigned_64'Alignment;
679
680   type pthread_key_t is new unsigned;
681
682end System.OS_Interface;
683