1 ------------------------------------------------------------------------------
3 -- 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 --
9 -- Copyright (C) 1992-2006, Free Software Foundation, Inc. --
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 2, 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. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
20 -- Boston, MA 02110-1301, USA. --
22 -- As a special exception, if other files instantiate generics from this --
23 -- unit, or you link this unit with other files to produce an executable, --
24 -- this unit does not by itself cause the resulting executable to be --
25 -- covered by the GNU General Public License. This exception does not --
26 -- however invalidate any other reasons why the executable file might be --
27 -- covered by the GNU Public License. --
29 -- GNAT was originally developed by the GNAT team at New York University. --
30 -- Extensive contributions were provided by Ada Core Technologies Inc. --
32 ------------------------------------------------------------------------------
34 -- This package is included in all programs. It contains declarations that
35 -- are required to be part of every Ada program. A special mechanism is
36 -- required to ensure that these are loaded, since it may be the case in
37 -- some programs that the only references to these required packages are
38 -- from C code or from code generated directly by Gigi, an in both cases
39 -- the binder is not aware of such references.
41 -- System.Standard_Library also includes data that must be present in every
42 -- program, in particular the definitions of all the standard and also some
43 -- subprograms that must be present in every program.
45 -- The binder unconditionally includes s-stalib.ali, which ensures that this
46 -- package and the packages it references are included in all Ada programs,
47 -- together with the included data.
50 -- We must turn polling off for this unit, because otherwise we get
51 -- elaboration circularities with Ada.Exceptions if polling is on.
54 with Unchecked_Conversion
;
56 package System
.Standard_Library
is
57 pragma Warnings
(Off
);
58 pragma Preelaborate_05
;
61 type Big_String_Ptr
is access all String (Positive);
62 -- A non-fat pointer type for null terminated strings
65 new Unchecked_Conversion
(System
.Address
, Big_String_Ptr
);
67 ---------------------------------------------
68 -- Type For Enumeration Image Index Tables --
69 ---------------------------------------------
71 -- Note: these types are declared at the start of this unit, since
72 -- they must appear before any enumeration types declared in this
73 -- unit. Note that the spec of system is already elaborated at
74 -- this point (since we are a child of system), which means that
75 -- enumeration types in package System cannot use these types.
77 type Image_Index_Table_8
is
78 array (Integer range <>) of Short_Short_Integer;
79 type Image_Index_Table_16
is
80 array (Integer range <>) of Short_Integer;
81 type Image_Index_Table_32
is
82 array (Integer range <>) of Integer;
83 -- These types are used to generate the index vector used for enumeration
84 -- type image tables. See spec of Exp_Imgv in the main GNAT sources for a
85 -- full description of the data structures that are used here.
87 -------------------------------------
88 -- Exception Declarations and Data --
89 -------------------------------------
91 type Raise_Action
is access procedure;
92 -- A pointer to a procedure used in the Raise_Hook field
95 type Exception_Data_Ptr
is access all Exception_Data
;
96 -- An equivalent of Exception_Id that is public
98 type Exception_Code
is mod 2 ** Integer'Size;
99 -- A scalar value bound to some exception data. Typically used for
100 -- imported or exported exceptions on VMS. Having a separate type for this
101 -- is useful to enforce consistency throughout the various run-time units
102 -- handling such codes, and having it unsigned is the most appropriate
103 -- choice for it's currently single use on VMS.
105 -- ??? The construction in Cstand has no way to access the proper type
106 -- node for Exception_Code, and currently uses Standard_Unsigned as a
107 -- fallback. The representations shall match, and the size clause below
108 -- is aimed at ensuring that.
110 for Exception_Code
'Size use Integer'Size;
112 -- The following record defines the underlying representation of exceptions
114 -- WARNING! Any changes to this may need to be reflectd in the following
115 -- locations in the compiler and runtime code:
117 -- 1. The Internal_Exception routine in s-exctab.adb
118 -- 2. The processing in gigi that tests Not_Handled_By_Others
119 -- 3. Expand_N_Exception_Declaration in Exp_Ch11
120 -- 4. The construction of the exception type in Cstand
122 type Exception_Data
is record
123 Not_Handled_By_Others
: Boolean;
124 -- Normally set False, indicating that the exception is handled in the
125 -- usual way by others (i.e. an others handler handles the exception).
126 -- Set True to indicate that this exception is not caught by others
127 -- handlers, but must be explicitly named in a handler. This latter
128 -- setting is currently used by the Abort_Signal.
131 -- A character indicating the language raising the exception.
132 -- Set to "A" for exceptions defined by an Ada program.
133 -- Set to "V" for imported VMS exceptions.
135 Name_Length
: Natural;
136 -- Length of fully expanded name of exception
138 Full_Name
: System
.Address
;
139 -- Fully expanded name of exception, null terminated
140 -- You can use To_Ptr to convert this to a string.
142 HTable_Ptr
: Exception_Data_Ptr
;
143 -- Hash table pointer used to link entries together in the hash table
144 -- built (by Register_Exception in s-exctab.adb) for converting between
145 -- identities and names.
147 Import_Code
: Exception_Code
;
148 -- Value for imported exceptions. Needed only for the handling of
149 -- Import/Export_Exception for the VMS case, but present in all
150 -- implementations (we might well extend this mechanism for other
151 -- systems in the future).
153 Raise_Hook
: Raise_Action
;
154 -- This field can be used to place a "hook" on an exception. If the
155 -- value is non-null, then it points to a procedure which is called
156 -- whenever the exception is raised. This call occurs immediately,
157 -- before any other actions taken by the raise (and in particular
158 -- before any unwinding of the stack occurs).
161 -- Definitions for standard predefined exceptions defined in Standard,
163 -- Why are the Nul's necessary here, seems like they should not be
164 -- required, since Gigi is supposed to add a Nul to each name ???
166 Constraint_Error_Name
: constant String := "CONSTRAINT_ERROR" & ASCII
.NUL
;
167 Program_Error_Name
: constant String := "PROGRAM_ERROR" & ASCII
.NUL
;
168 Storage_Error_Name
: constant String := "STORAGE_ERROR" & ASCII
.NUL
;
169 Tasking_Error_Name
: constant String := "TASKING_ERROR" & ASCII
.NUL
;
170 Abort_Signal_Name
: constant String := "_ABORT_SIGNAL" & ASCII
.NUL
;
172 Numeric_Error_Name
: constant String := "NUMERIC_ERROR" & ASCII
.NUL
;
173 -- This is used only in the Ada 83 case, but it is not worth having a
174 -- separate version of s-stalib.ads for use in Ada 83 mode.
176 Constraint_Error_Def
: aliased Exception_Data
:=
177 (Not_Handled_By_Others
=> False,
179 Name_Length
=> Constraint_Error_Name
'Length,
180 Full_Name
=> Constraint_Error_Name
'Address,
185 Numeric_Error_Def
: aliased Exception_Data
:=
186 (Not_Handled_By_Others
=> False,
188 Name_Length
=> Numeric_Error_Name
'Length,
189 Full_Name
=> Numeric_Error_Name
'Address,
194 Program_Error_Def
: aliased Exception_Data
:=
195 (Not_Handled_By_Others
=> False,
197 Name_Length
=> Program_Error_Name
'Length,
198 Full_Name
=> Program_Error_Name
'Address,
203 Storage_Error_Def
: aliased Exception_Data
:=
204 (Not_Handled_By_Others
=> False,
206 Name_Length
=> Storage_Error_Name
'Length,
207 Full_Name
=> Storage_Error_Name
'Address,
212 Tasking_Error_Def
: aliased Exception_Data
:=
213 (Not_Handled_By_Others
=> False,
215 Name_Length
=> Tasking_Error_Name
'Length,
216 Full_Name
=> Tasking_Error_Name
'Address,
221 Abort_Signal_Def
: aliased Exception_Data
:=
222 (Not_Handled_By_Others
=> True,
224 Name_Length
=> Abort_Signal_Name
'Length,
225 Full_Name
=> Abort_Signal_Name
'Address,
230 pragma Export
(C
, Constraint_Error_Def
, "constraint_error");
231 pragma Export
(C
, Numeric_Error_Def
, "numeric_error");
232 pragma Export
(C
, Program_Error_Def
, "program_error");
233 pragma Export
(C
, Storage_Error_Def
, "storage_error");
234 pragma Export
(C
, Tasking_Error_Def
, "tasking_error");
235 pragma Export
(C
, Abort_Signal_Def
, "_abort_signal");
237 Local_Partition_ID
: Natural := 0;
238 -- This variable contains the local Partition_ID that will be used when
239 -- building exception occurrences. In distributed mode, it will be
240 -- set by each partition to the correct value during the elaboration.
242 type Exception_Trace_Kind
is
244 -- No particular trace is requested, only unhandled exceptions
245 -- in the environment task (following the RM) will be printed.
246 -- This is the default behavior.
249 -- Denotes every possible raise event, either explicit or due to
250 -- a specific language rule, within the context of a task or not.
253 -- Denotes the raise events corresponding to exceptions for which
254 -- there is no user defined handler.
256 -- Provide a way to denote different kinds of automatic traces related
257 -- to exceptions that can be requested.
259 Exception_Trace
: Exception_Trace_Kind
:= RM_Convention
;
260 pragma Atomic
(Exception_Trace
);
261 -- By default, follow the RM convention
267 procedure Abort_Undefer_Direct
;
268 pragma Inline
(Abort_Undefer_Direct
);
269 -- A little procedure that just calls Abort_Undefer.all, for use in
270 -- clean up procedures, which only permit a simple subprogram name.
273 -- Performs the Ada Runtime finalization the first time it is invoked.
274 -- All subsequent calls are ignored.
276 end System
.Standard_Library
;