gcc/ada/libgnat/g-stsifd__sockets.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --     G N A T . S O C K E T S . T H I N . S I G N A L L I N G _ F D S      --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --                     Copyright (C) 2001-2023, AdaCore                     --
  10 --                                                                          --
  11 -- GNAT 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 -- GNAT was originally developed  by the GNAT team at  New York University. --
  28 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  29 --                                                                          --
  30 ------------------------------------------------------------------------------
  31
  32 --  Portable sockets-based implementation of GNAT.Sockets.Thin.Signalling_Fds
  33 --  used for platforms that do not support UNIX pipes.
  34
  35 --  Note: this code used to be in GNAT.Sockets, but has been moved to a
  36 --  platform-specific file. It is now used only for non-UNIX platforms.
  37
  38 separate (GNAT.Sockets.Thin)
  39 package body Signalling_Fds is
  40
  41    -----------
  42    -- Close --
  43    -----------
  44
  45    procedure Close (Sig : C.int) is
  46       Res : C.int;
  47       pragma Unreferenced (Res);
  48       --  Res is assigned but never read, because we purposefully ignore
  49       --  any error returned by the C_Close system call, as per the spec
  50       --  of this procedure.
  51    begin
  52       Res := C_Close (Sig);
  53    end Close;
  54
  55    ------------
  56    -- Create --
  57    ------------
  58
  59    function Create (Fds : not null access Fd_Pair) return C.int is
  60       Res : constant C.int :=
  61               C_Socketpair (SOSC.AF_INET, SOSC.SOCK_STREAM, 0, Fds);
  62    begin
  63       if Res /= Failure then
  64          --  Set TCP_NODELAY on Fds (Write_End), since we always want to send
  65          --  the data out immediately.
  66
  67          Set_Socket_Option
  68            (Socket => Socket_Type (Fds (Write_End)),
  69             Level  => IP_Protocol_For_TCP_Level,
  70             Option => (Name => No_Delay, Enabled => True));
  71       end if;
  72
  73       return Res;
  74    end Create;
  75
  76    ----------
  77    -- Read --
  78    ----------
  79
  80    function Read (Rsig : C.int) return C.int is
  81       Buf : aliased Character;
  82    begin
  83       return C_Recv (Rsig, Buf'Address, 1, SOSC.MSG_Forced_Flags);
  84    end Read;
  85
  86    -----------
  87    -- Write --
  88    -----------
  89
  90    function Write (Wsig : C.int) return C.int is
  91       Buf : aliased Character := ASCII.NUL;
  92    begin
  93       return C_Sendto
  94         (Wsig, Buf'Address, 1,
  95          Flags => SOSC.MSG_Forced_Flags,
  96          To    => System.Null_Address,
  97          Tolen => 0);
  98    end Write;
  99
 100 end Signalling_Fds;