gcc/ada/g-stseme.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                  GNAT.SOCKETS.THIN.SOCKET_ERROR_MESSAGE                  --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --                     Copyright (C) 2007-2009, 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 --  This is the default implementation of this unit, using the standard C
  33 --  library's strerror(3) function. It is used on all platforms except Windows,
  34 --  since on that platform socket errno values are distinct from the system
  35 --  ones: there is a specific variant of this function in g-socthi-mingw.adb.
  36
  37 with Ada.Unchecked_Conversion;
  38
  39 with System.CRTL;
  40
  41 separate (GNAT.Sockets.Thin)
  42
  43 --------------------------
  44 -- Socket_Error_Message --
  45 --------------------------
  46
  47 function Socket_Error_Message
  48   (Errno : Integer) return C.Strings.chars_ptr
  49 is
  50    use type Interfaces.C.Strings.chars_ptr;
  51
  52    pragma Warnings (Off);
  53    function To_Chars_Ptr is
  54      new Ada.Unchecked_Conversion
  55        (System.Address, Interfaces.C.Strings.chars_ptr);
  56    --  On VMS, the compiler warns because System.Address is 64 bits, but
  57    --  chars_ptr is 32 bits. It should be safe, though, because strerror
  58    --  will return a 32-bit pointer.
  59    pragma Warnings (On);
  60
  61    C_Msg : C.Strings.chars_ptr;
  62
  63 begin
  64    C_Msg := To_Chars_Ptr (System.CRTL.strerror (Errno));
  65
  66    if C_Msg = C.Strings.Null_Ptr then
  67       return Unknown_System_Error;
  68    else
  69       return C_Msg;
  70    end if;
  71 end Socket_Error_Message;