1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT COMPILER COMPONENTS                         --
4--                                                                          --
5--                    S Y S T E M . P A R A M E T E R S                     --
6--                                                                          --
7--                                 B o d y                                  --
8--                                                                          --
9--          Copyright (C) 1995-2018, Free Software Foundation, Inc.         --
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 (used on all native platforms) version of this package
33
34pragma Compiler_Unit_Warning;
35
36package body System.Parameters is
37
38   -------------------------
39   -- Adjust_Storage_Size --
40   -------------------------
41
42   function Adjust_Storage_Size (Size : Size_Type) return Size_Type is
43   begin
44      if Size = Unspecified_Size then
45         return Default_Stack_Size;
46      elsif Size < Minimum_Stack_Size then
47         return Minimum_Stack_Size;
48      else
49         return Size;
50      end if;
51   end Adjust_Storage_Size;
52
53   ------------------------
54   -- Default_Stack_Size --
55   ------------------------
56
57   function Default_Stack_Size return Size_Type is
58      Default_Stack_Size : Integer;
59      pragma Import (C, Default_Stack_Size, "__gl_default_stack_size");
60   begin
61      if Default_Stack_Size = -1 then
62         return 2 * 1024 * 1024;
63      else
64         return Size_Type (Default_Stack_Size);
65      end if;
66   end Default_Stack_Size;
67
68   ------------------------
69   -- Minimum_Stack_Size --
70   ------------------------
71
72   function Minimum_Stack_Size return Size_Type is
73   begin
74      --  12K is required for stack-checking to work reliably on most platforms
75      --  when using the GCC scheme to propagate an exception in the ZCX case.
76      --  16K is the value of PTHREAD_STACK_MIN under Linux, so is a reasonable
77      --  default.
78
79      return 16 * 1024;
80   end Minimum_Stack_Size;
81
82end System.Parameters;
83