------------------------------------------------------------------------------ -- -- -- GNAT RUN-TIME COMPONENTS -- -- -- -- S Y S T E M . M E M O R Y -- -- -- -- S p e c -- -- -- -- Copyright (C) 2001-2003 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- -- -- 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 -- -- 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 -- -- 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. -- -- -- -- GNAT was originally developed by the GNAT team at New York University. -- -- Extensive contributions were provided by Ada Core Technologies Inc. -- -- -- ------------------------------------------------------------------------------ -- This package provides the low level memory allocation/deallocation -- mechanisms used by GNAT. -- To provide an alternate implementation, simply recompile the modified -- body of this package with gnatmake -u -a -g s-memory.adb and make sure -- that the ali and object files for this unit are found in the object -- search path. -- This unit may be used directly from an application program by providing -- an appropriate WITH, and the interface can be expected to remain stable. package System.Memory is pragma Elaborate_Body; type size_t is mod 2 ** Standard'Address_Size; -- Note: the reason we redefine this here instead of using the -- definition in Interfaces.C is that we do not want to drag in -- all of Interfaces.C just because System.Memory is used. function Alloc (Size : size_t) return System.Address; -- This is the low level allocation routine. Given a size in storage -- units, it returns the address of a maximally aligned block of -- memory. The implementation of this routine is guaranteed to be -- task safe, and also aborts are deferred if necessary. -- -- If size_t is set to size_t'Last on entry, then a Storage_Error -- exception is raised with a message "object too large". -- -- If size_t is set to zero on entry, then a minimal (but non-zero) -- size block is allocated. -- -- Note: this is roughly equivalent to the standard C malloc call -- with the additional semantics as described above. procedure Free (Ptr : System.Address); -- This is the low level free routine. It frees a block previously -- allocated with a call to Alloc. As in the case of Alloc, this -- call is guaranteed task safe, and aborts are deferred. -- -- Note: this is roughly equivalent to the standard C free call -- with the additional semantics as described above. function Realloc (Ptr : System.Address; Size : size_t) return System.Address; -- This is the low level reallocation routine. It takes an existing -- block address returned by a previous call to Alloc or Realloc, -- and reallocates the block. The size can either be increased or -- decreased. If possible the reallocation is done in place, so that -- the returned result is the same as the value of Ptr on entry. -- However, it may be necessary to relocate the block to another -- address, in which case the information is copied to the new -- block, and the old block is freed. The implementation of this -- routine is guaranteed to be task safe, and also aborts are -- deferred as necessary. -- -- If size_t is set to size_t'Last on entry, then a Storage_Error -- exception is raised with a message "object too large". -- -- If size_t is set to zero on entry, then a minimal (but non-zero) -- size block is allocated. -- -- Note: this is roughly equivalent to the standard C realloc call -- with the additional semantics as described above. private -- The following names are used from the generated compiler code pragma Export (C, Alloc, "__gnat_malloc"); pragma Export (C, Free, "__gnat_free"); pragma Export (C, Realloc, "__gnat_realloc"); end System.Memory;