gcc/ada/libgnat/s-osprim__posix.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                 GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS                 --
   4 --                                                                          --
   5 --                  S Y S T E M . O S _ P R I M I T I V E S                 --
   6 --                                                                          --
   7 --                                  B o d y                                 --
   8 --                                                                          --
   9 --          Copyright (C) 1998-2024, Free Software Foundation, Inc.         --
  10 --                                                                          --
  11 -- GNARL is free software; you can  redistribute it  and/or modify it under --
  12 -- terms of the  GNU General Public License as published  by the Free Soft- --
  13 -- ware  Foundation;  either version 3,  or (at your option) any later ver- --
  14 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  15 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  16 -- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
  17 --                                                                          --
  18 -- As a special exception under Section 7 of GPL version 3, you are granted --
  19 -- additional permissions described in the GCC Runtime Library Exception,   --
  20 -- version 3.1, as published by the Free Software Foundation.               --
  21 --                                                                          --
  22 -- You should have received a copy of the GNU General Public License and    --
  23 -- a copy of the GCC Runtime Library Exception along with this program;     --
  24 -- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
  25 -- <http://www.gnu.org/licenses/>.                                          --
  26 --                                                                          --
  27 -- GNARL was developed by the GNARL team at Florida State University.       --
  28 -- Extensive contributions were provided by Ada Core Technologies, Inc.     --
  29 --                                                                          --
  30 ------------------------------------------------------------------------------
  31
  32 --  This version is for POSIX-like operating systems
  33 with System.Parameters;
  34
  35 package body System.OS_Primitives is
  36
  37    --  ??? These definitions are duplicated from System.OS_Interface
  38    --  because we don't want to depend on any package. Consider removing
  39    --  these declarations in System.OS_Interface and move these ones in
  40    --  the spec.
  41
  42    type time_t is range -2 ** (System.Parameters.time_t_bits - 1)
  43      .. 2 ** (System.Parameters.time_t_bits - 1) - 1;
  44
  45    type timespec is record
  46       tv_sec  : time_t;
  47       tv_nsec : Long_Integer;
  48    end record;
  49    pragma Convention (C, timespec);
  50
  51    function nanosleep (rqtp, rmtp : not null access timespec) return Integer;
  52    pragma Import (C, nanosleep, "nanosleep");
  53
  54    -----------
  55    -- Clock --
  56    -----------
  57
  58    function Clock return Duration is
  59
  60       type timeval is array (1 .. 3) of Long_Integer;
  61       --  The timeval array is sized to contain Long_Long_Integer sec and
  62       --  Long_Integer usec. If Long_Long_Integer'Size = Long_Integer'Size then
  63       --  it will be overly large but that will not effect the implementation
  64       --  since it is not accessed directly.
  65
  66       procedure timeval_to_duration
  67         (T    : not null access timeval;
  68          sec  : not null access Long_Long_Integer;
  69          usec : not null access Long_Integer);
  70       pragma Import (C, timeval_to_duration, "__gnat_timeval_to_duration");
  71
  72       Micro  : constant := 10**6;
  73       sec    : aliased Long_Long_Integer;
  74       usec   : aliased Long_Integer;
  75       TV     : aliased timeval;
  76       Result : Integer;
  77       pragma Unreferenced (Result);
  78
  79       function gettimeofday
  80         (Tv : access timeval;
  81          Tz : System.Address := System.Null_Address) return Integer;
  82       pragma Import (C, gettimeofday, "gettimeofday");
  83
  84    begin
  85       --  The return codes for gettimeofday are as follows (from man pages):
  86       --    EPERM  settimeofday is called by someone other than the superuser
  87       --    EINVAL Timezone (or something else) is invalid
  88       --    EFAULT One of tv or tz pointed outside accessible address space
  89
  90       --  None of these codes signal a potential clock skew, hence the return
  91       --  value is never checked.
  92
  93       Result := gettimeofday (TV'Access, System.Null_Address);
  94       timeval_to_duration (TV'Access, sec'Access, usec'Access);
  95       return Duration (sec) + Duration (usec) / Micro;
  96    end Clock;
  97
  98    -----------------
  99    -- To_Timespec --
 100    -----------------
 101
 102    function To_Timespec (D : Duration) return timespec;
 103
 104    function To_Timespec (D : Duration) return timespec is
 105       S : time_t;
 106       F : Duration;
 107
 108    begin
 109       S := time_t (Long_Long_Integer (D));
 110       F := D - Duration (S);
 111
 112       --  If F has negative value due to a round-up, adjust for positive F
 113       --  value.
 114
 115       if F < 0.0 then
 116          S := S - 1;
 117          F := F + 1.0;
 118       end if;
 119
 120       return
 121         timespec'(tv_sec  => S,
 122                   tv_nsec => Long_Integer (Long_Long_Integer (F * 10#1#E9)));
 123    end To_Timespec;
 124
 125    -----------------
 126    -- Timed_Delay --
 127    -----------------
 128
 129    procedure Timed_Delay
 130      (Time : Duration;
 131       Mode : Integer)
 132    is separate;
 133
 134    ----------------
 135    -- Initialize --
 136    ----------------
 137
 138    procedure Initialize is
 139    begin
 140       null;
 141    end Initialize;
 142
 143 end System.OS_Primitives;