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1 ------------------------------------------------------------------------------
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2 -- --
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3 -- GNAT RUN-TIME COMPONENTS --
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4 -- --
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5 -- A D A . S Y N C H R O N O U S _ B A R R I E R S --
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6 -- --
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7 -- B o d y --
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8 -- --
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9 -- Copyright (C) 1992-2017, Free Software Foundation, Inc. --
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10 -- --
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11 -- This specification is derived from the Ada Reference Manual for use with --
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12 -- GNAT. The copyright notice above, and the license provisions that follow --
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13 -- apply solely to the contents of the part following the private keyword. --
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14 -- --
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15 -- GNAT is free software; you can redistribute it and/or modify it under --
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16 -- terms of the GNU General Public License as published by the Free Soft- --
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17 -- ware Foundation; either version 3, or (at your option) any later ver- --
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18 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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19 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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20 -- or FITNESS FOR A PARTICULAR PURPOSE. --
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21 -- --
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22 -- As a special exception under Section 7 of GPL version 3, you are granted --
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23 -- additional permissions described in the GCC Runtime Library Exception, --
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24 -- version 3.1, as published by the Free Software Foundation. --
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25 -- --
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26 -- You should have received a copy of the GNU General Public License and --
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27 -- a copy of the GCC Runtime Library Exception along with this program; --
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28 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
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29 -- <http://www.gnu.org/licenses/>. --
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30 -- --
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31 -- GNAT was originally developed by the GNAT team at New York University. --
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32 -- Extensive contributions were provided by Ada Core Technologies Inc. --
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33 -- --
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34 ------------------------------------------------------------------------------
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35
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36 -- This is the body of this package using POSIX barriers
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37
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38 with Interfaces.C; use Interfaces.C;
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39
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40 package body Ada.Synchronous_Barriers is
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41
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42 --------------------
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43 -- POSIX barriers --
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44 --------------------
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45
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46 function pthread_barrier_init
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47 (barrier : not null access pthread_barrier_t;
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48 attr : System.Address := System.Null_Address;
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49 count : unsigned) return int;
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50 pragma Import (C, pthread_barrier_init, "pthread_barrier_init");
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51 -- Initialize barrier with the attributes in attr. The barrier is opened
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52 -- when count waiters arrived. If attr is null the default barrier
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53 -- attributes are used.
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54
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55 function pthread_barrier_destroy
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56 (barrier : not null access pthread_barrier_t) return int;
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57 pragma Import (C, pthread_barrier_destroy, "pthread_barrier_destroy");
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58 -- Destroy a previously dynamically initialized barrier
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59
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60 function pthread_barrier_wait
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61 (barrier : not null access pthread_barrier_t) return int;
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62 pragma Import (C, pthread_barrier_wait, "pthread_barrier_wait");
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63 -- Wait on barrier
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64
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65 --------------
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66 -- Finalize --
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67 --------------
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68
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69 overriding procedure Finalize (Barrier : in out Synchronous_Barrier) is
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70 Result : int;
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71 begin
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72 Result := pthread_barrier_destroy (Barrier.POSIX_Barrier'Access);
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73 pragma Assert (Result = 0);
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74 end Finalize;
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75
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76 overriding procedure Initialize (Barrier : in out Synchronous_Barrier) is
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77 Result : int;
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78 begin
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79 Result :=
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80 pthread_barrier_init
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81 (barrier => Barrier.POSIX_Barrier'Access,
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82 attr => System.Null_Address,
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83 count => unsigned (Barrier.Release_Threshold));
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84 pragma Assert (Result = 0);
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85 end Initialize;
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86
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87 ----------------------
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88 -- Wait_For_Release --
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89 ----------------------
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90
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91 procedure Wait_For_Release
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92 (The_Barrier : in out Synchronous_Barrier;
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93 Notified : out Boolean)
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94 is
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95 Result : int;
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96
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97 PTHREAD_BARRIER_SERIAL_THREAD : constant := -1;
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98 -- Value used to indicate the task which receives the notification for
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99 -- the barrier open.
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100
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101 begin
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102 Result :=
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103 pthread_barrier_wait
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104 (barrier => The_Barrier.POSIX_Barrier'Access);
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105 pragma Assert
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106 (Result = 0 or else Result = PTHREAD_BARRIER_SERIAL_THREAD);
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107
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108 Notified := (Result = PTHREAD_BARRIER_SERIAL_THREAD);
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109 end Wait_For_Release;
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110
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111 end Ada.Synchronous_Barriers;
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