gcc/ada/s-osinte-kfreebsd-gnu.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                GNU ADA 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) 1991-1994, Florida State University          --
  10 --            Copyright (C) 1995-2016, 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 the GNU/kFreeBSD (POSIX Threads) version of this package
  34
  35 --  This package encapsulates all direct interfaces to OS services
  36 --  that are needed by children of System.
  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
  41 with Interfaces.C;
  42 with Unchecked_Conversion;
  43
  44 package System.OS_Interface is
  45    pragma Preelaborate;
  46
  47    pragma Linker_Options ("-lpthread");
  48
  49    subtype int            is Interfaces.C.int;
  50    subtype char           is Interfaces.C.char;
  51    subtype short          is Interfaces.C.short;
  52    subtype long           is Interfaces.C.long;
  53    subtype unsigned       is Interfaces.C.unsigned;
  54    subtype unsigned_short is Interfaces.C.unsigned_short;
  55    subtype unsigned_long  is Interfaces.C.unsigned_long;
  56    subtype unsigned_char  is Interfaces.C.unsigned_char;
  57    subtype plain_char     is Interfaces.C.plain_char;
  58    subtype size_t         is Interfaces.C.size_t;
  59
  60    -----------
  61    -- Errno --
  62    -----------
  63
  64    function errno return int;
  65    pragma Import (C, errno, "__get_errno");
  66
  67    EAGAIN   : constant := 35;
  68    EINTR    : constant := 4;
  69    EINVAL   : constant := 22;
  70    ENOMEM   : constant := 12;
  71    EPERM    : constant := 1;
  72    ETIMEDOUT    : constant := 60;
  73
  74    -------------
  75    -- Signals --
  76    -------------
  77
  78    Max_Interrupt : constant := 128;
  79    type Signal is new int range 0 .. Max_Interrupt;
  80    for Signal'Size use int'Size;
  81
  82    SIGHUP     : constant := 1; --  hangup
  83    SIGINT     : constant := 2; --  interrupt (rubout)
  84    SIGQUIT    : constant := 3; --  quit (ASCD FS)
  85    SIGILL     : constant := 4; --  illegal instruction (not reset)
  86    SIGTRAP    : constant := 5; --  trace trap (not reset)
  87    SIGIOT     : constant := 6; --  IOT instruction
  88    SIGABRT    : constant := 6; --  used by abort, replace SIGIOT in the  future
  89    SIGEMT     : constant := 7; --  EMT instruction
  90    SIGFPE     : constant := 8; --  floating point exception
  91    SIGKILL    : constant := 9; --  kill (cannot be caught or ignored)
  92    SIGBUS     : constant := 10; --  bus error
  93    SIGSEGV    : constant := 11; --  segmentation violation
  94    SIGSYS     : constant := 12; --  bad argument to system call
  95    SIGPIPE    : constant := 13; --  write on a pipe with no one to read it
  96    SIGALRM    : constant := 14; --  alarm clock
  97    SIGTERM    : constant := 15; --  software termination signal from kill
  98    SIGURG     : constant := 16; --  urgent condition on IO channel
  99    SIGSTOP    : constant := 17; --  stop (cannot be caught or ignored)
 100    SIGTSTP    : constant := 18; --  user stop requested from tty
 101    SIGCONT    : constant := 19; --  stopped process has been continued
 102    SIGCLD     : constant := 20; --  alias for SIGCHLD
 103    SIGCHLD    : constant := 20; --  child status change
 104    SIGTTIN    : constant := 21; --  background tty read attempted
 105    SIGTTOU    : constant := 22; --  background tty write attempted
 106    SIGIO      : constant := 23; --  I/O possible (Solaris SIGPOLL alias)
 107    SIGXCPU    : constant := 24; --  CPU time limit exceeded
 108    SIGXFSZ    : constant := 25; --  filesize limit exceeded
 109    SIGVTALRM  : constant := 26; --  virtual timer expired
 110    SIGPROF    : constant := 27; --  profiling timer expired
 111    SIGWINCH   : constant := 28; --  window size change
 112    SIGINFO    : constant := 29; --  information request (NetBSD/FreeBSD)
 113    SIGUSR1    : constant := 30; --  user defined signal 1
 114    SIGUSR2    : constant := 31; --  user defined signal 2
 115    SIGLTHRRES : constant := 32; --  GNU/LinuxThreads restart signal
 116    SIGLTHRCAN : constant := 33; --  GNU/LinuxThreads cancel signal
 117    SIGLTHRDBG : constant := 34; --  GNU/LinuxThreads debugger signal
 118
 119    SIGADAABORT : constant := SIGABRT;
 120    --  Change this if you want to use another signal for task abort.
 121    --  SIGTERM might be a good one.
 122
 123    type Signal_Set is array (Natural range <>) of Signal;
 124
 125    Unmasked    : constant Signal_Set := (
 126       SIGTRAP,
 127       --  To enable debugging on multithreaded applications, mark SIGTRAP to
 128       --  be kept unmasked.
 129
 130       SIGBUS,
 131
 132       SIGTTIN, SIGTTOU, SIGTSTP,
 133       --  Keep these three signals unmasked so that background processes
 134       --  and IO behaves as normal "C" applications
 135
 136       SIGPROF,
 137       --  To avoid confusing the profiler
 138
 139       SIGKILL, SIGSTOP,
 140       --  These two signals actually cannot be masked;
 141       --  POSIX simply won't allow it.
 142
 143       SIGLTHRRES, SIGLTHRCAN, SIGLTHRDBG);
 144       --  These three signals are used by GNU/LinuxThreads starting from
 145       --  glibc 2.1 (future 2.2).
 146
 147    Reserved    : constant Signal_Set :=
 148    --  I am not sure why the following signal is reserved.
 149    --  I guess they are not supported by this version of GNU/kFreeBSD.
 150      (0 .. 0 => SIGVTALRM);
 151
 152    type sigset_t is private;
 153
 154    function sigaddset (set : access sigset_t; sig : Signal) return int;
 155    pragma Import (C, sigaddset, "sigaddset");
 156
 157    function sigdelset (set : access sigset_t; sig : Signal) return int;
 158    pragma Import (C, sigdelset, "sigdelset");
 159
 160    function sigfillset (set : access sigset_t) return int;
 161    pragma Import (C, sigfillset, "sigfillset");
 162
 163    function sigismember (set : access sigset_t; sig : Signal) return int;
 164    pragma Import (C, sigismember, "sigismember");
 165
 166    function sigemptyset (set : access sigset_t) return int;
 167    pragma Import (C, sigemptyset, "sigemptyset");
 168
 169    --  sigcontext is architecture dependent, so define it private
 170    type struct_sigcontext is private;
 171
 172    type struct_sigaction is record
 173       sa_handler : System.Address;
 174       sa_flags   : int;
 175       sa_mask    : sigset_t;
 176    end record;
 177    pragma Convention (C, struct_sigaction);
 178
 179    type struct_sigaction_ptr is access all struct_sigaction;
 180
 181    SIG_BLOCK   : constant := 1;
 182    SIG_UNBLOCK : constant := 2;
 183    SIG_SETMASK : constant := 3;
 184
 185    SIG_DFL : constant := 0;
 186    SIG_IGN : constant := 1;
 187
 188    SA_SIGINFO : constant := 16#0040#;
 189    SA_ONSTACK : constant := 16#0001#;
 190
 191    function sigaction
 192      (sig  : Signal;
 193       act  : struct_sigaction_ptr;
 194       oact : struct_sigaction_ptr) return int;
 195    pragma Import (C, sigaction, "sigaction");
 196
 197    ----------
 198    -- Time --
 199    ----------
 200
 201    Time_Slice_Supported : constant Boolean := True;
 202    --  Indicates whether time slicing is supported (i.e SCHED_RR is supported)
 203
 204    type timespec is private;
 205
 206    function nanosleep (rqtp, rmtp : access timespec) return int;
 207    pragma Import (C, nanosleep, "nanosleep");
 208
 209    type clockid_t is private;
 210
 211    CLOCK_REALTIME : constant clockid_t;
 212
 213    function clock_gettime
 214      (clock_id : clockid_t;
 215       tp       : access timespec)
 216       return int;
 217    pragma Import (C, clock_gettime, "clock_gettime");
 218
 219    function clock_getres
 220      (clock_id : clockid_t;
 221       res      : access timespec) return int;
 222    pragma Import (C, clock_getres, "clock_getres");
 223
 224    function To_Duration (TS : timespec) return Duration;
 225    pragma Inline (To_Duration);
 226
 227    function To_Timespec (D : Duration) return timespec;
 228    pragma Inline (To_Timespec);
 229
 230    function sysconf (name : int) return long;
 231    pragma Import (C, sysconf);
 232
 233    SC_CLK_TCK          : constant := 2;
 234    SC_NPROCESSORS_ONLN : constant := 84;
 235
 236    -------------------------
 237    -- Priority Scheduling --
 238    -------------------------
 239
 240    SCHED_FIFO  : constant := 1;
 241    SCHED_OTHER : constant := 2;
 242    SCHED_RR    : constant := 3;
 243
 244    function To_Target_Priority
 245      (Prio : System.Any_Priority) return Interfaces.C.int;
 246    --  Maps System.Any_Priority to a POSIX priority.
 247
 248    -------------
 249    -- Process --
 250    -------------
 251
 252    type pid_t is private;
 253
 254    function kill (pid : pid_t; sig : Signal) return int;
 255    pragma Import (C, kill, "kill");
 256
 257    function getpid return pid_t;
 258    pragma Import (C, getpid, "getpid");
 259
 260    ---------
 261    -- LWP --
 262    ---------
 263
 264    function lwp_self return System.Address;
 265    --  lwp_self does not exist on this thread library, revert to pthread_self
 266    --  which is the closest approximation (with getpid). This function is
 267    --  needed to share 7staprop.adb across POSIX-like targets.
 268    pragma Import (C, lwp_self, "pthread_self");
 269
 270    -------------
 271    -- Threads --
 272    -------------
 273
 274    type Thread_Body is access
 275      function (arg : System.Address) return System.Address;
 276    pragma Convention (C, Thread_Body);
 277
 278    function Thread_Body_Access is new
 279      Unchecked_Conversion (System.Address, Thread_Body);
 280
 281    type pthread_t is new unsigned_long;
 282    subtype Thread_Id        is pthread_t;
 283
 284    function To_pthread_t is new Unchecked_Conversion
 285      (unsigned_long, pthread_t);
 286
 287    type pthread_mutex_t     is limited private;
 288    type pthread_cond_t      is limited private;
 289    type pthread_attr_t      is limited private;
 290    type pthread_mutexattr_t is limited private;
 291    type pthread_condattr_t  is limited private;
 292    type pthread_key_t       is private;
 293
 294    PTHREAD_CREATE_DETACHED : constant := 1;
 295    PTHREAD_CREATE_JOINABLE : constant := 0;
 296
 297    PTHREAD_SCOPE_PROCESS : constant := 0;
 298    PTHREAD_SCOPE_SYSTEM  : constant := 2;
 299
 300    --  Read/Write lock not supported on kfreebsd. To add support both types
 301    --  pthread_rwlock_t and pthread_rwlockattr_t must properly be defined
 302    --  with the associated routines pthread_rwlock_[init/destroy] and
 303    --  pthread_rwlock_[rdlock/wrlock/unlock].
 304
 305    subtype pthread_rwlock_t     is pthread_mutex_t;
 306    subtype pthread_rwlockattr_t is pthread_mutexattr_t;
 307
 308    -----------
 309    -- Stack --
 310    -----------
 311
 312    type stack_t is record
 313       ss_sp    : System.Address;
 314       ss_size  : size_t;
 315       ss_flags : int;
 316    end record;
 317    pragma Convention (C, stack_t);
 318
 319    function sigaltstack
 320      (ss  : not null access stack_t;
 321       oss : access stack_t) return int;
 322    pragma Import (C, sigaltstack, "sigaltstack");
 323
 324    Alternate_Stack : aliased System.Address;
 325    --  This is a dummy definition, never used (Alternate_Stack_Size is null)
 326
 327    Alternate_Stack_Size : constant := 0;
 328    --  No alternate signal stack is used on this platform
 329
 330    Stack_Base_Available : constant Boolean := False;
 331    --  Indicates whether the stack base is available on this target
 332
 333    function Get_Stack_Base (thread : pthread_t) return Address;
 334    pragma Inline (Get_Stack_Base);
 335    --  returns the stack base of the specified thread. Only call this function
 336    --  when Stack_Base_Available is True.
 337
 338    function Get_Page_Size return int;
 339    pragma Import (C, Get_Page_Size, "getpagesize");
 340    --  Returns the size of a page
 341
 342    PROT_NONE  : constant := 0;
 343    PROT_READ  : constant := 1;
 344    PROT_WRITE : constant := 2;
 345    PROT_EXEC  : constant := 4;
 346    PROT_ALL   : constant := PROT_READ + PROT_WRITE + PROT_EXEC;
 347    PROT_ON    : constant := PROT_NONE;
 348    PROT_OFF   : constant := PROT_ALL;
 349
 350    function mprotect (addr : Address; len : size_t; prot : int) return int;
 351    pragma Import (C, mprotect);
 352
 353    ---------------------------------------
 354    -- Nonstandard Thread Initialization --
 355    ---------------------------------------
 356
 357    procedure pthread_init;
 358    pragma Inline (pthread_init);
 359    --  This is a dummy procedure to share some GNULLI files
 360
 361    -------------------------
 362    -- POSIX.1c  Section 3 --
 363    -------------------------
 364
 365    function sigwait (set : access sigset_t; sig : access Signal) return int;
 366    pragma Import (C, sigwait, "sigwait");
 367
 368    function pthread_kill (thread : pthread_t; sig : Signal) return int;
 369    pragma Import (C, pthread_kill, "pthread_kill");
 370
 371    function pthread_sigmask
 372      (how  : int;
 373       set  : access sigset_t;
 374       oset : access sigset_t) return int;
 375    pragma Import (C, pthread_sigmask, "pthread_sigmask");
 376
 377    --------------------------
 378    -- POSIX.1c  Section 11 --
 379    --------------------------
 380
 381    function pthread_mutexattr_init
 382      (attr : access pthread_mutexattr_t) return int;
 383    pragma Import (C, pthread_mutexattr_init, "pthread_mutexattr_init");
 384
 385    function pthread_mutexattr_destroy
 386      (attr : access pthread_mutexattr_t) return int;
 387    pragma Import (C, pthread_mutexattr_destroy, "pthread_mutexattr_destroy");
 388
 389    function pthread_mutex_init
 390      (mutex : access pthread_mutex_t;
 391       attr  : access pthread_mutexattr_t) return int;
 392    pragma Import (C, pthread_mutex_init, "pthread_mutex_init");
 393
 394    function pthread_mutex_destroy (mutex : access pthread_mutex_t) return int;
 395    pragma Import (C, pthread_mutex_destroy, "pthread_mutex_destroy");
 396
 397    function pthread_mutex_lock (mutex : access pthread_mutex_t) return int;
 398    pragma Import (C, pthread_mutex_lock, "pthread_mutex_lock");
 399
 400    function pthread_mutex_unlock (mutex : access pthread_mutex_t) return int;
 401    pragma Import (C, pthread_mutex_unlock, "pthread_mutex_unlock");
 402
 403    function pthread_condattr_init
 404      (attr : access pthread_condattr_t) return int;
 405    pragma Import (C, pthread_condattr_init, "pthread_condattr_init");
 406
 407    function pthread_condattr_destroy
 408      (attr : access pthread_condattr_t) return int;
 409    pragma Import (C, pthread_condattr_destroy, "pthread_condattr_destroy");
 410
 411    function pthread_cond_init
 412      (cond : access pthread_cond_t;
 413       attr : access pthread_condattr_t) return int;
 414    pragma Import (C, pthread_cond_init, "pthread_cond_init");
 415
 416    function pthread_cond_destroy (cond : access pthread_cond_t) return int;
 417    pragma Import (C, pthread_cond_destroy, "pthread_cond_destroy");
 418
 419    function pthread_cond_signal (cond : access pthread_cond_t) return int;
 420    pragma Import (C, pthread_cond_signal, "pthread_cond_signal");
 421
 422    function pthread_cond_wait
 423      (cond  : access pthread_cond_t;
 424       mutex : access pthread_mutex_t) return int;
 425    pragma Import (C, pthread_cond_wait, "pthread_cond_wait");
 426
 427    function pthread_cond_timedwait
 428      (cond    : access pthread_cond_t;
 429       mutex   : access pthread_mutex_t;
 430       abstime : access timespec) return int;
 431    pragma Import (C, pthread_cond_timedwait, "pthread_cond_timedwait");
 432
 433    Relative_Timed_Wait : constant Boolean := False;
 434    --  pthread_cond_timedwait requires an absolute delay time
 435
 436    --------------------------
 437    -- POSIX.1c  Section 13 --
 438    --------------------------
 439
 440    PTHREAD_PRIO_NONE    : constant := 0;
 441    PTHREAD_PRIO_PROTECT : constant := 2;
 442    PTHREAD_PRIO_INHERIT : constant := 1;
 443
 444    function pthread_mutexattr_setprotocol
 445      (attr     : access pthread_mutexattr_t;
 446       protocol : int) return int;
 447    pragma Import
 448       (C, pthread_mutexattr_setprotocol, "pthread_mutexattr_setprotocol");
 449
 450    function pthread_mutexattr_getprotocol
 451      (attr     : access pthread_mutexattr_t;
 452       protocol : access int) return int;
 453    pragma Import
 454      (C, pthread_mutexattr_getprotocol, "pthread_mutexattr_getprotocol");
 455
 456    function pthread_mutexattr_setprioceiling
 457      (attr     : access pthread_mutexattr_t;
 458       prioceiling : int) return int;
 459    pragma Import
 460      (C, pthread_mutexattr_setprioceiling,
 461       "pthread_mutexattr_setprioceiling");
 462
 463    function pthread_mutexattr_getprioceiling
 464      (attr     : access pthread_mutexattr_t;
 465       prioceiling : access int) return int;
 466    pragma Import
 467      (C, pthread_mutexattr_getprioceiling,
 468       "pthread_mutexattr_getprioceiling");
 469
 470    type struct_sched_param is record
 471       sched_priority : int;  --  scheduling priority
 472    end record;
 473    pragma Convention (C, struct_sched_param);
 474
 475    function pthread_setschedparam
 476      (thread : pthread_t;
 477       policy : int;
 478       param  : access struct_sched_param) return int;
 479    pragma Import (C, pthread_setschedparam, "pthread_setschedparam");
 480
 481    function pthread_attr_setscope
 482      (attr            : access pthread_attr_t;
 483       contentionscope : int) return int;
 484    pragma Import (C, pthread_attr_setscope, "pthread_attr_setscope");
 485
 486    function pthread_attr_getscope
 487      (attr            : access pthread_attr_t;
 488       contentionscope : access int) return int;
 489    pragma Import (C, pthread_attr_getscope, "pthread_attr_getscope");
 490
 491    function pthread_attr_setinheritsched
 492      (attr            : access pthread_attr_t;
 493       inheritsched : int) return int;
 494    pragma Import
 495      (C, pthread_attr_setinheritsched, "pthread_attr_setinheritsched");
 496
 497    function pthread_attr_getinheritsched
 498      (attr         : access pthread_attr_t;
 499       inheritsched : access int) return int;
 500    pragma Import
 501      (C, pthread_attr_getinheritsched, "pthread_attr_getinheritsched");
 502
 503    function pthread_attr_setschedpolicy
 504      (attr   : access pthread_attr_t;
 505       policy : int) return int;
 506    pragma Import
 507      (C, pthread_attr_setschedpolicy, "pthread_attr_setschedpolicy");
 508
 509    function sched_yield return int;
 510    pragma Import (C, sched_yield, "sched_yield");
 511
 512    ---------------------------
 513    -- P1003.1c - Section 16 --
 514    ---------------------------
 515
 516    function pthread_attr_init
 517      (attributes : access pthread_attr_t) return int;
 518    pragma Import (C, pthread_attr_init, "pthread_attr_init");
 519
 520    function pthread_attr_destroy
 521      (attributes : access pthread_attr_t) return int;
 522    pragma Import (C, pthread_attr_destroy, "pthread_attr_destroy");
 523
 524    function pthread_attr_setdetachstate
 525      (attr        : access pthread_attr_t;
 526       detachstate : int) return int;
 527    pragma Import
 528      (C, pthread_attr_setdetachstate, "pthread_attr_setdetachstate");
 529
 530    function pthread_attr_setstacksize
 531      (attr      : access pthread_attr_t;
 532       stacksize : size_t) return int;
 533    pragma Import (C, pthread_attr_setstacksize, "pthread_attr_setstacksize");
 534
 535    function pthread_create
 536      (thread        : access pthread_t;
 537       attributes    : access pthread_attr_t;
 538       start_routine : Thread_Body;
 539       arg           : System.Address) return int;
 540    pragma Import (C, pthread_create, "pthread_create");
 541
 542    procedure pthread_exit (status : System.Address);
 543    pragma Import (C, pthread_exit, "pthread_exit");
 544
 545    function pthread_self return pthread_t;
 546    pragma Import (C, pthread_self, "pthread_self");
 547
 548    --------------------------
 549    -- POSIX.1c  Section 17 --
 550    --------------------------
 551
 552    function pthread_setspecific
 553      (key   : pthread_key_t;
 554       value : System.Address) return int;
 555    pragma Import (C, pthread_setspecific, "pthread_setspecific");
 556
 557    function pthread_getspecific (key : pthread_key_t) return System.Address;
 558    pragma Import (C, pthread_getspecific, "pthread_getspecific");
 559
 560    type destructor_pointer is access procedure (arg : System.Address);
 561    pragma Convention (C, destructor_pointer);
 562
 563    function pthread_key_create
 564      (key        : access pthread_key_t;
 565       destructor : destructor_pointer) return int;
 566    pragma Import (C, pthread_key_create, "pthread_key_create");
 567
 568    CPU_SETSIZE : constant := 1_024;
 569
 570    type bit_field is array (1 .. CPU_SETSIZE) of Boolean;
 571    for bit_field'Size use CPU_SETSIZE;
 572    pragma Pack (bit_field);
 573    pragma Convention (C, bit_field);
 574
 575    type cpu_set_t is record
 576       bits : bit_field;
 577    end record;
 578    pragma Convention (C, cpu_set_t);
 579
 580    function pthread_setaffinity_np
 581      (thread     : pthread_t;
 582       cpusetsize : size_t;
 583       cpuset     : access cpu_set_t) return int;
 584    pragma Import (C, pthread_setaffinity_np, "__gnat_pthread_setaffinity_np");
 585
 586 private
 587
 588    type sigset_t is array (1 .. 4) of unsigned;
 589
 590    --  In FreeBSD the component sa_handler turns out to
 591    --  be one a union type, and the selector is a macro:
 592    --  #define sa_handler __sigaction_u._handler
 593    --  #define sa_sigaction __sigaction_u._sigaction
 594
 595    --  Should we add a signal_context type here ?
 596    --  How could it be done independent of the CPU architecture ?
 597    --  sigcontext type is opaque, so it is architecturally neutral.
 598    --  It is always passed as an access type, so define it as an empty record
 599    --  since the contents are not used anywhere.
 600    type struct_sigcontext is null record;
 601    pragma Convention (C, struct_sigcontext);
 602
 603    type pid_t is new int;
 604
 605    type time_t is new long;
 606
 607    type timespec is record
 608       tv_sec  : time_t;
 609       tv_nsec : long;
 610    end record;
 611    pragma Convention (C, timespec);
 612
 613    type clockid_t is new int;
 614    CLOCK_REALTIME : constant clockid_t := 0;
 615
 616    type pthread_attr_t is record
 617       detachstate   : int;
 618       schedpolicy   : int;
 619       schedparam    : struct_sched_param;
 620       inheritsched  : int;
 621       scope         : int;
 622       guardsize     : size_t;
 623       stackaddr_set : int;
 624       stackaddr     : System.Address;
 625       stacksize     : size_t;
 626    end record;
 627    pragma Convention (C, pthread_attr_t);
 628
 629    type pthread_condattr_t is record
 630       dummy : int;
 631    end record;
 632    pragma Convention (C, pthread_condattr_t);
 633
 634    type pthread_mutexattr_t is record
 635       mutexkind : int;
 636    end record;
 637    pragma Convention (C, pthread_mutexattr_t);
 638
 639    type struct_pthread_fast_lock is record
 640       status   : long;
 641       spinlock : int;
 642    end record;
 643    pragma Convention (C, struct_pthread_fast_lock);
 644
 645    type pthread_mutex_t is record
 646       m_reserved : int;
 647       m_count    : int;
 648       m_owner    : System.Address;
 649       m_kind     : int;
 650       m_lock     : struct_pthread_fast_lock;
 651    end record;
 652    pragma Convention (C, pthread_mutex_t);
 653
 654    type pthread_cond_t is array (0 .. 47) of unsigned_char;
 655    pragma Convention (C, pthread_cond_t);
 656
 657    type pthread_key_t is new unsigned;
 658
 659 end System.OS_Interface;