File : s-stalib.ads


     ------------------------------------------------------------------------------
     --                                                                          --
     --                         GNAT COMPILER COMPONENTS                         --
     --                                                                          --
   5 --              S Y S T E M . S T A N D A R D _ L I B R A R Y               --
     --                                                                          --
     --                                 S p e c                                  --
     --                                                                          --
     --                            $Revision: 1.43 $
  10 --                                                                          --
     --          Copyright (C) 1992-2001 Free Software Foundation, Inc.          --
     --                                                                          --
     -- GNAT is free software;  you can  redistribute it  and/or modify it under --
     -- terms of the  GNU General Public License as published  by the Free Soft- --
  15 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
     -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
     -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
     -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
     -- for  more details.  You should have  received  a copy of the GNU General --
  20 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
     -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
     -- MA 02111-1307, USA.                                                      --
     --                                                                          --
     -- As a special exception,  if other files  instantiate  generics from this --
  25 -- unit, or you link  this unit with other files  to produce an executable, --
     -- this  unit  does not  by itself cause  the resulting  executable  to  be --
     -- covered  by the  GNU  General  Public  License.  This exception does not --
     -- however invalidate  any other reasons why  the executable file  might be --
     -- covered by the  GNU Public License.                                      --
  30 --                                                                          --
     -- GNAT was originally developed  by the GNAT team at  New York University. --
     -- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
     --                                                                          --
     ------------------------------------------------------------------------------
  35 
     --  This package is included in all programs. It contains declarations that
     --  are required to be part of every Ada program. A special mechanism is
     --  required to ensure that these are loaded, since it may be the case in
     --  some programs that the only references to these required packages are
  40 --  from C code or from code generated directly by Gigi, an in both cases
     --  the binder is not aware of such references.
     
     --  System.Standard_Library also includes data that must be present in every
     --  program, in particular the definitions of all the standard and also some
  45 --  subprograms that must be present in every program.
     
     --  The binder unconditionally includes s-stalib.ali, which ensures that this
     --  package and the packages it references are included in all Ada programs,
     --  together with the included data.
  50 
     pragma Polling (Off);
     --  We must turn polling off for this unit, because otherwise we get
     --  elaboration circularities with Ada.Exceptions if polling is on.
     
  55 with System;
     with Unchecked_Conversion;
     
     package System.Standard_Library is
     
  60    pragma Suppress (All_Checks);
        --  Suppress explicitely all the checks to work around the Solaris linker
        --  bug when using gnatmake -f -a (but without -gnatp). This is not needed
        --  with Solaris 2.6, so eventually can be removed ???
     
  65    type Big_String_Ptr is access all String (Positive);
        --  A non-fat pointer type for null terminated strings
     
        function To_Ptr is
          new Unchecked_Conversion (System.Address, Big_String_Ptr);
  70 
        ---------------------------------------------
        -- Type For Enumeration Image Index Tables --
        ---------------------------------------------
     
  75    --  Note: these types are declared at the start of this unit, since
        --  they must appear before any enumeration types declared in this
        --  unit. Note that the spec of system is already elaborated at
        --  this point (since we are a child of system), which means that
        --  enumeration types in package System cannot use these types.
  80 
        type Image_Index_Table_8 is
          array (Integer range <>) of Short_Short_Integer;
        type Image_Index_Table_16 is
          array (Integer range <>) of Short_Integer;
  85    type Image_Index_Table_32 is
          array (Integer range <>) of Integer;
        --  These types are used to generate the index vector used for enumeration
        --  type image tables. See spec of Exp_Imgv in the main GNAT sources for a
        --  full description of the data structures that are used here.
  90 
        -------------------------------------
        -- Exception Declarations and Data --
        -------------------------------------
     
  95    type Exception_Data;
        type Exception_Data_Ptr is access all Exception_Data;
        --  An equivalent of Exception_Id that is public
     
        --  The following record defines the underlying representation of exceptions
 100 
        --  WARNING! Any changes to this may need to be reflectd in the following
        --  locations in the compiler and runtime code:
     
        --    1. The Internal_Exception routine in s-exctab.adb
 105    --    2. The processing in gigi that tests Not_Handled_By_Others
        --    3. Expand_N_Exception_Declaration in Exp_Ch11
        --    4. The construction of the exception type in Cstand
     
        type Exception_Data is record
 110       Not_Handled_By_Others : Boolean;
           --  Normally set False, indicating that the exception is handled in the
           --  usual way by others (i.e. an others handler handles the exception).
           --  Set True to indicate that this exception is not caught by others
           --  handlers, but must be explicitly named in a handler. This latter
 115       --  setting is currently used by the Abort_Signal.
     
           Lang : Character;
           --  A character indicating the language raising the exception.
           --  Set to "A" for exceptions defined by an Ada program.
 120       --  Set to "V" for imported VMS exceptions.
     
           Name_Length : Natural;
           --  Length of fully expanded name of exception
     
 125       Full_Name : Big_String_Ptr;
           --  Fully expanded name of exception, null terminated
     
           HTable_Ptr : Exception_Data_Ptr;
           --  Hash table pointer used to link entries together in the hash table
 130       --  built (by Register_Exception in s-exctab.adb) for converting between
           --  identities and names.
     
           Import_Code : Integer;
           --  Value for imported exceptions. Needed only for the handling of
 135       --  Import/Export_Exception for the VMS case, but present in all
           --  implementations (we might well extend this mechanism for other
           --  systems in the future).
     
        end record;
 140 
        --  Definitions for standard predefined exceptions defined in Standard,
     
        --  Why are the Nul's necessary here, seems like they should not be
        --  required, since Gigi is supposed to add a Nul to each name ???
 145 
        Constraint_Error_Name : constant String := "CONSTRAINT_ERROR" & ASCII.NUL;
        Program_Error_Name    : constant String := "PROGRAM_ERROR"    & ASCII.NUL;
        Storage_Error_Name    : constant String := "STORAGE_ERROR"    & ASCII.NUL;
        Tasking_Error_Name    : constant String := "TASKING_ERROR"    & ASCII.NUL;
 150    Abort_Signal_Name     : constant String := "_ABORT_SIGNAL"    & ASCII.NUL;
     
        Numeric_Error_Name    : constant String := "NUMERIC_ERROR"    & ASCII.NUL;
        --  This is used only in the Ada 83 case, but it is not worth having a
        --  separate version of s-stalib.ads for use in Ada 83 mode.
 155 
        Constraint_Error_Def : aliased Exception_Data :=
          (Not_Handled_By_Others => False,
           Lang                  => 'A',
           Name_Length           => Constraint_Error_Name'Length,
 160       Full_Name             => To_Ptr (Constraint_Error_Name'Address),
           HTable_Ptr            => null,
           Import_Code           => 0);
     
        Numeric_Error_Def : aliased Exception_Data :=
 165      (Not_Handled_By_Others => False,
           Lang                  => 'A',
           Name_Length           => Numeric_Error_Name'Length,
           Full_Name             => To_Ptr (Numeric_Error_Name'Address),
           HTable_Ptr            => null,
 170       Import_Code           => 0);
     
        Program_Error_Def : aliased Exception_Data :=
          (Not_Handled_By_Others => False,
           Lang                  => 'A',
 175       Name_Length           => Program_Error_Name'Length,
           Full_Name             => To_Ptr (Program_Error_Name'Address),
           HTable_Ptr            => null,
           Import_Code           => 0);
     
 180    Storage_Error_Def : aliased Exception_Data :=
          (Not_Handled_By_Others => False,
           Lang                  => 'A',
           Name_Length           => Storage_Error_Name'Length,
           Full_Name             => To_Ptr (Storage_Error_Name'Address),
 185       HTable_Ptr            => null,
           Import_Code           => 0);
     
        Tasking_Error_Def : aliased Exception_Data :=
          (Not_Handled_By_Others => False,
 190       Lang                  => 'A',
           Name_Length           => Tasking_Error_Name'Length,
           Full_Name             => To_Ptr (Tasking_Error_Name'Address),
           HTable_Ptr            => null,
           Import_Code           => 0);
 195 
        Abort_Signal_Def : aliased Exception_Data :=
          (Not_Handled_By_Others => True,
           Lang                  => 'A',
           Name_Length           => Abort_Signal_Name'Length,
 200       Full_Name             => To_Ptr (Abort_Signal_Name'Address),
           HTable_Ptr            => null,
           Import_Code           => 0);
     
        pragma Export (C, Constraint_Error_Def, "constraint_error");
 205    pragma Export (C, Numeric_Error_Def,    "numeric_error");
        pragma Export (C, Program_Error_Def,    "program_error");
        pragma Export (C, Storage_Error_Def,    "storage_error");
        pragma Export (C, Tasking_Error_Def,    "tasking_error");
        pragma Export (C, Abort_Signal_Def,     "_abort_signal");
 210 
        Local_Partition_ID : Natural := 0;
        --  This variable contains the local Partition_ID that will be used when
        --  building exception occurrences. In distributed mode, it will be
        --  set by each partition to the correct value during the elaboration.
 215 
        type Exception_Trace_Kind is
          (RM_Convention,
           --  No particular trace is requested, only unhandled exceptions
           --  in the environment task (following the RM) will be printed.
 220       --  This is the default behavior.
     
           Every_Raise,
           --  Denotes every possible raise event, either explicit or due to
           --  a specific language rule, within the context of a task or not.
 225 
           Unhandled_Raise
           --  Denotes the raise events corresponding to exceptions for which
           --  there is no user defined handler.
          );
 230    --  Provide a way to denote different kinds of automatic traces related
        --  to exceptions that can be requested.
     
        Exception_Trace : Exception_Trace_Kind := RM_Convention;
        pragma Atomic (Exception_Trace);
 235    --  By default, follow the RM convention.
     
        -----------------
        -- Subprograms --
        -----------------
 240 
        procedure Abort_Undefer_Direct;
        pragma Inline (Abort_Undefer_Direct);
        --  A little procedure that just calls Abort_Undefer.all, for use in
        --  clean up procedures, which only permit a simple subprogram name.
 245 
        procedure Adafinal;
        --  Performs the Ada Runtime finalization the first time it is invoked.
        --  All subsequent calls are ignored.
     
 250 end System.Standard_Library;