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) 1992-2008, 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.
49 pragma Warnings
(Off
);
54 -- We must turn polling off for this unit, because otherwise we get
55 -- elaboration circularities with Ada.Exceptions if polling is on.
58 with Ada
.Unchecked_Conversion
;
60 package System
.Standard_Library
is
61 pragma Warnings
(Off
);
62 pragma Preelaborate_05
;
65 type Big_String_Ptr
is access all String (Positive);
66 for Big_String_Ptr
'Storage_Size use 0;
67 -- A non-fat pointer type for null terminated strings
70 new Ada
.Unchecked_Conversion
(System
.Address
, Big_String_Ptr
);
72 ---------------------------------------------
73 -- Type For Enumeration Image Index Tables --
74 ---------------------------------------------
76 -- Note: these types are declared at the start of this unit, since
77 -- they must appear before any enumeration types declared in this
78 -- unit. Note that the spec of system is already elaborated at
79 -- this point (since we are a child of system), which means that
80 -- enumeration types in package System cannot use these types.
82 type Image_Index_Table_8
is
83 array (Integer range <>) of Short_Short_Integer;
84 type Image_Index_Table_16
is
85 array (Integer range <>) of Short_Integer;
86 type Image_Index_Table_32
is
87 array (Integer range <>) of Integer;
88 -- These types are used to generate the index vector used for enumeration
89 -- type image tables. See spec of Exp_Imgv in the main GNAT sources for a
90 -- full description of the data structures that are used here.
92 -------------------------------------
93 -- Exception Declarations and Data --
94 -------------------------------------
96 type Raise_Action
is access procedure;
97 -- A pointer to a procedure used in the Raise_Hook field
100 type Exception_Data_Ptr
is access all Exception_Data
;
101 -- An equivalent of Exception_Id that is public
103 type Exception_Code
is mod 2 ** Integer'Size;
104 -- A scalar value bound to some exception data. Typically used for
105 -- imported or exported exceptions on VMS. Having a separate type for this
106 -- is useful to enforce consistency throughout the various run-time units
107 -- handling such codes, and having it unsigned is the most appropriate
108 -- choice for it's currently single use on VMS.
110 -- ??? The construction in Cstand has no way to access the proper type
111 -- node for Exception_Code, and currently uses Standard_Unsigned as a
112 -- fallback. The representations shall match, and the size clause below
113 -- is aimed at ensuring that.
115 for Exception_Code
'Size use Integer'Size;
117 -- The following record defines the underlying representation of exceptions
119 -- WARNING! Any changes to this may need to be reflected in the following
120 -- locations in the compiler and runtime code:
122 -- 1. The Internal_Exception routine in s-exctab.adb
123 -- 2. The processing in gigi that tests Not_Handled_By_Others
124 -- 3. Expand_N_Exception_Declaration in Exp_Ch11
125 -- 4. The construction of the exception type in Cstand
127 type Exception_Data
is record
128 Not_Handled_By_Others
: Boolean;
129 -- Normally set False, indicating that the exception is handled in the
130 -- usual way by others (i.e. an others handler handles the exception).
131 -- Set True to indicate that this exception is not caught by others
132 -- handlers, but must be explicitly named in a handler. This latter
133 -- setting is currently used by the Abort_Signal.
136 -- A character indicating the language raising the exception.
137 -- Set to "A" for exceptions defined by an Ada program.
138 -- Set to "V" for imported VMS exceptions.
140 Name_Length
: Natural;
141 -- Length of fully expanded name of exception
143 Full_Name
: System
.Address
;
144 -- Fully expanded name of exception, null terminated
145 -- You can use To_Ptr to convert this to a string.
147 HTable_Ptr
: Exception_Data_Ptr
;
148 -- Hash table pointer used to link entries together in the hash table
149 -- built (by Register_Exception in s-exctab.adb) for converting between
150 -- identities and names.
152 Import_Code
: Exception_Code
;
153 -- Value for imported exceptions. Needed only for the handling of
154 -- Import/Export_Exception for the VMS case, but present in all
155 -- implementations (we might well extend this mechanism for other
156 -- systems in the future).
158 Raise_Hook
: Raise_Action
;
159 -- This field can be used to place a "hook" on an exception. If the
160 -- value is non-null, then it points to a procedure which is called
161 -- whenever the exception is raised. This call occurs immediately,
162 -- before any other actions taken by the raise (and in particular
163 -- before any unwinding of the stack occurs).
166 -- Definitions for standard predefined exceptions defined in Standard,
168 -- Why are the NULs necessary here, seems like they should not be
169 -- required, since Gigi is supposed to add a Nul to each name ???
171 Constraint_Error_Name
: constant String := "CONSTRAINT_ERROR" & ASCII
.NUL
;
172 Program_Error_Name
: constant String := "PROGRAM_ERROR" & ASCII
.NUL
;
173 Storage_Error_Name
: constant String := "STORAGE_ERROR" & ASCII
.NUL
;
174 Tasking_Error_Name
: constant String := "TASKING_ERROR" & ASCII
.NUL
;
175 Abort_Signal_Name
: constant String := "_ABORT_SIGNAL" & ASCII
.NUL
;
177 Numeric_Error_Name
: constant String := "NUMERIC_ERROR" & ASCII
.NUL
;
178 -- This is used only in the Ada 83 case, but it is not worth having a
179 -- separate version of s-stalib.ads for use in Ada 83 mode.
181 Constraint_Error_Def
: aliased Exception_Data
:=
182 (Not_Handled_By_Others
=> False,
184 Name_Length
=> Constraint_Error_Name
'Length,
185 Full_Name
=> Constraint_Error_Name
'Address,
190 Numeric_Error_Def
: aliased Exception_Data
:=
191 (Not_Handled_By_Others
=> False,
193 Name_Length
=> Numeric_Error_Name
'Length,
194 Full_Name
=> Numeric_Error_Name
'Address,
199 Program_Error_Def
: aliased Exception_Data
:=
200 (Not_Handled_By_Others
=> False,
202 Name_Length
=> Program_Error_Name
'Length,
203 Full_Name
=> Program_Error_Name
'Address,
208 Storage_Error_Def
: aliased Exception_Data
:=
209 (Not_Handled_By_Others
=> False,
211 Name_Length
=> Storage_Error_Name
'Length,
212 Full_Name
=> Storage_Error_Name
'Address,
217 Tasking_Error_Def
: aliased Exception_Data
:=
218 (Not_Handled_By_Others
=> False,
220 Name_Length
=> Tasking_Error_Name
'Length,
221 Full_Name
=> Tasking_Error_Name
'Address,
226 Abort_Signal_Def
: aliased Exception_Data
:=
227 (Not_Handled_By_Others
=> True,
229 Name_Length
=> Abort_Signal_Name
'Length,
230 Full_Name
=> Abort_Signal_Name
'Address,
235 pragma Export
(C
, Constraint_Error_Def
, "constraint_error");
236 pragma Export
(C
, Numeric_Error_Def
, "numeric_error");
237 pragma Export
(C
, Program_Error_Def
, "program_error");
238 pragma Export
(C
, Storage_Error_Def
, "storage_error");
239 pragma Export
(C
, Tasking_Error_Def
, "tasking_error");
240 pragma Export
(C
, Abort_Signal_Def
, "_abort_signal");
242 Local_Partition_ID
: Natural := 0;
243 -- This variable contains the local Partition_ID that will be used when
244 -- building exception occurrences. In distributed mode, it will be
245 -- set by each partition to the correct value during the elaboration.
247 type Exception_Trace_Kind
is
249 -- No particular trace is requested, only unhandled exceptions
250 -- in the environment task (following the RM) will be printed.
251 -- This is the default behavior.
254 -- Denotes every possible raise event, either explicit or due to
255 -- a specific language rule, within the context of a task or not.
258 -- Denotes the raise events corresponding to exceptions for which
259 -- there is no user defined handler.
261 -- Provide a way to denote different kinds of automatic traces related
262 -- to exceptions that can be requested.
264 Exception_Trace
: Exception_Trace_Kind
:= RM_Convention
;
265 pragma Atomic
(Exception_Trace
);
266 -- By default, follow the RM convention
272 procedure Abort_Undefer_Direct
;
273 pragma Inline
(Abort_Undefer_Direct
);
274 -- A little procedure that just calls Abort_Undefer.all, for use in
275 -- clean up procedures, which only permit a simple subprogram name.
278 -- Performs the Ada Runtime finalization the first time it is invoked.
279 -- All subsequent calls are ignored.
281 end System
.Standard_Library
;