gcc/ada/a-caldel.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                 GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS                 --
   4 --                                                                          --
   5 --                   A D A . C A L E N D A R . D E L A Y S                  --
   6 --                                                                          --
   7 --                                  B o d y                                 --
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   9 --             Copyright (C) 1991-1994, Florida State University            --
  10 --                     Copyright (C) 1995-2008, AdaCore                     --
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  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 --
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  30 -- GNARL was developed by the GNARL team at Florida State University.       --
  31 -- Extensive contributions were provided by Ada Core Technologies, Inc.     --
  32 --                                                                          --
  33 ------------------------------------------------------------------------------
  34
  35 with System.OS_Primitives;
  36 with System.Soft_Links;
  37 with System.Traces;
  38 with System.Parameters;
  39
  40 package body Ada.Calendar.Delays is
  41
  42    package OSP renames System.OS_Primitives;
  43    package SSL renames System.Soft_Links;
  44
  45    use type SSL.Timed_Delay_Call;
  46
  47    use System.Traces;
  48
  49    --  Earlier, System.Time_Operations was used to implement the following
  50    --  operations. The idea was to avoid sucking in the tasking packages. This
  51    --  did not work. Logically, we can't have it both ways. There is no way to
  52    --  implement time delays that will have correct task semantics without
  53    --  reference to the tasking run-time system. To achieve this goal, we now
  54    --  use soft links.
  55
  56    -----------------------
  57    -- Local Subprograms --
  58    -----------------------
  59
  60    procedure Timed_Delay_NT (Time : Duration; Mode : Integer);
  61    --  Timed delay procedure used when no tasking is active
  62
  63    ---------------
  64    -- Delay_For --
  65    ---------------
  66
  67    procedure Delay_For (D : Duration) is
  68    begin
  69       if System.Parameters.Runtime_Traces then
  70          Send_Trace_Info (W_Delay, D);
  71       end if;
  72
  73       SSL.Timed_Delay.all (Duration'Min (D, OSP.Max_Sensible_Delay),
  74                            OSP.Relative);
  75
  76       if System.Parameters.Runtime_Traces then
  77          Send_Trace_Info (M_Delay, D);
  78       end if;
  79    end Delay_For;
  80
  81    -----------------
  82    -- Delay_Until --
  83    -----------------
  84
  85    procedure Delay_Until (T : Time) is
  86       D : constant Duration := To_Duration (T);
  87
  88    begin
  89       if System.Parameters.Runtime_Traces then
  90          Send_Trace_Info (WU_Delay, D);
  91       end if;
  92
  93       SSL.Timed_Delay.all (D, OSP.Absolute_Calendar);
  94
  95       if System.Parameters.Runtime_Traces then
  96          Send_Trace_Info (M_Delay, D);
  97       end if;
  98    end Delay_Until;
  99
 100    --------------------
 101    -- Timed_Delay_NT --
 102    --------------------
 103
 104    procedure Timed_Delay_NT (Time : Duration; Mode : Integer) is
 105    begin
 106       OSP.Timed_Delay (Time, Mode);
 107    end Timed_Delay_NT;
 108
 109    -----------------
 110    -- To_Duration --
 111    -----------------
 112
 113    function To_Duration (T : Time) return Duration is
 114    begin
 115       --  Since time has multiple representations on different platforms, a
 116       --  target independent operation in Ada.Calendar is used to perform
 117       --  this conversion.
 118
 119       return Delay_Operations.To_Duration (T);
 120    end To_Duration;
 121
 122 begin
 123    --  Set up the Timed_Delay soft link to the non tasking version if it has
 124    --  not been already set. If tasking is present, Timed_Delay has already set
 125    --  this soft link, or this will be overridden during the elaboration of
 126    --  System.Tasking.Initialization
 127
 128    if SSL.Timed_Delay = null then
 129       SSL.Timed_Delay := Timed_Delay_NT'Access;
 130    end if;
 131
 132 end Ada.Calendar.Delays;