I changed lmem.c to look like this:
------------- code block start ----------------
/*
** $Id: lmem.c,v 1.61 2002/12/04 17:38:31 roberto Exp $
** Interface to Memory Manager
** See Copyright Notice in lua.h
*/
#include <stdlib.h>
#define lmem_c
#include "lua.h"
#include "ldebug.h"
#include "ldo.h"
#include "lmem.h"
#include "lobject.h"
#include "lstate.h"
#include "Windows.h"
/*
** definition for realloc function. It must assure that l_realloc(NULL,
** 0, x) allocates a new block (ANSI C assures that). (`os' is the old
** block size; some allocators may use that.)
*/
#ifndef l_realloc
//#define l_realloc(b,os,s) realloc(b,s)
#endif
/*
** definition for free function. (`os' is the old block size; some
** allocators may use that.)
*/
#ifndef l_free
#define l_free(b,os) HeapFree(GetProcessHeap(),0,b);
//#define l_free(b,os) free(b)
#endif
#define MINSIZEARRAY 4
void *luaM_growaux (lua_State *L, void *block, int *size, int size_elems,
int limit, const char *errormsg) {
void *newblock;
int newsize = (*size)*2;
if (newsize < MINSIZEARRAY)
newsize = MINSIZEARRAY; /* minimum size */
else if (*size >= limit/2) { /* cannot double it? */
if (*size < limit - MINSIZEARRAY) /* try something smaller... */
newsize = limit; /* still have at least MINSIZEARRAY free places */
else luaG_runerror(L, errormsg);
}
newblock = luaM_realloc(L, block,
cast(lu_mem, *size)*cast(lu_mem, size_elems),
cast(lu_mem, newsize)*cast(lu_mem, size_elems));
*size = newsize; /* update only when everything else is OK */
return newblock;
}
/*
** generic allocation routine.
*/
void *luaM_realloc (lua_State *L, void *block, lu_mem oldsize, lu_mem size) {
lua_assert((oldsize == 0) == (block == NULL));
if (size == 0) {
if (block != NULL) {
l_free(block, oldsize);
block = NULL;
}
else return NULL; /* avoid `nblocks' computations when oldsize==size==0 */
}
else if (size >= MAX_SIZET)
luaG_runerror(L, "memory allocation error: block too big");
else {
//block = l_realloc(block, oldsize, size);
if(block == NULL)
{
block = HeapAlloc(GetProcessHeap(),0,size);
} else
{
block = HeapReAlloc(GetProcessHeap(),0,block,size);
}
if (block == NULL) {
if (L)
luaD_throw(L, LUA_ERRMEM);
else return NULL; /* error before creating state! */
}
}
if (L) {
lua_assert(G(L) != NULL && G(L)->nblocks > 0);
G(L)->nblocks -= oldsize;
G(L)->nblocks += size;
}
return block;
}
------------- code block start ----------------
With those changes it works great with shared memory in Windows when linking Lua statically. I have been using this is a commercial product for a while now with no problems. If you do this, other Lua DLL modules may not work properly but if working with a closed system it works like a charm. You can link Lua statically in your app and in DLLs and they will not have memory issues this way.
- Brett
-----Original Message-----
Sent: Thursday, March 11, 2004 1:09 PM
Subject: shared memory access from within a Lua script..
I am _very_ new to Lua (I'd never heard of it before today) and I find
myself needing to write a Lua script for a project I'm working on.
I need to be able to move a fairly large amount of data from
within a Lua
script to the "outside" world where I can deal with it using another
program. The only way I know to do this is by constructing a shared
memory segment.
Has anyone ever done this before? If so, could someone point me to an
example?
Thanks!
g.
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