1 ------------------------------------------------------------------------------
3 -- GNAT RUN-TIME COMPONENTS --
5 -- S Y S T E M . M E M O R Y --
9 -- Copyright (C) 2001-2003 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, 59 Temple Place - Suite 330, Boston, --
20 -- MA 02111-1307, 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 is the default implementation of this package.
36 -- This implementation assumes that the underlying malloc/free/realloc
37 -- implementation is thread safe, and thus, no additional lock is required.
38 -- Note that we still need to defer abortion because on most systems,
39 -- an asynchronous signal (as used for implementing asynchronous abortion
40 -- of task) cannot safely be handled while malloc is executing.
42 -- If you are not using Ada constructs containing the "abort" keyword,
43 -- then you can remove the calls to Abort_Defer.all and Abort_Undefer.all
47 with System.Soft_Links;
48 with System.Parameters;
50 package body System.Memory is
53 use System.Soft_Links;
55 function c_malloc (Size : size_t) return System.Address;
56 pragma Import (C, c_malloc, "malloc");
58 procedure c_free (Ptr : System.Address);
59 pragma Import (C, c_free, "free");
62 (Ptr : System.Address; Size : size_t) return System.Address;
63 pragma Import (C, c_realloc, "realloc");
69 function Alloc (Size : size_t) return System.Address is
70 Result : System.Address;
71 Actual_Size : size_t := Size;
74 if Size = size_t'Last then
75 Raise_Exception (Storage_Error'Identity, "object too large");
78 -- Change size from zero to non-zero. We still want a proper pointer
79 -- for the zero case because pointers to zero length objects have to
80 -- be distinct, but we can't just go ahead and allocate zero bytes,
81 -- since some malloc's return zero for a zero argument.
87 if Parameters.No_Abort then
88 Result := c_malloc (Actual_Size);
91 Result := c_malloc (Actual_Size);
95 if Result = System.Null_Address then
96 Raise_Exception (Storage_Error'Identity, "heap exhausted");
106 procedure Free (Ptr : System.Address) is
108 if Parameters.No_Abort then
122 (Ptr : System.Address;
124 return System.Address
126 Result : System.Address;
127 Actual_Size : constant size_t := Size;
130 if Size = size_t'Last then
131 Raise_Exception (Storage_Error'Identity, "object too large");
134 if Parameters.No_Abort then
135 Result := c_realloc (Ptr, Actual_Size);
138 Result := c_realloc (Ptr, Actual_Size);
142 if Result = System.Null_Address then
143 Raise_Exception (Storage_Error'Identity, "heap exhausted");