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Hi folks!

This error originaly occurs in a big application, but to get a focus on in, I reproduced it in a small environment. Im using VisualStudio (VisualC++ 6.0). I created a standard dialog application with a text field and a button to call lua with the text.
This is the relevant code:

void CLuaDialogDlg::OnDo()
    lua_State *L = lua_open();  /* create state */
    if (L == NULL)
        MessageBox("cannot create state: not enough memory");

    CString code;
    int status=luaL_dostring(L,code);

    if (status && !lua_isnil(L, -1))
        const char *msg = lua_tostring(L, -1);
        if (msg == NULL) msg = "(error object is not a string)";
        lua_pop(L, 1);

This works fine for a lot of lua scripts. After fiddling the package.cpath and package.path (by adding a package.cpath="... lot of entries..." to the script) to point to my LuaForWindows installation I can also use lfs and other libs with no problems.

The trouble begins, when I try to use iuplua. The following code


shows the alarm, but then get a "unhandled exception" inside the lua_close. Interesting, even a


with no further code causes the crash.

The stacktrack shows up like this:

USER32! 7e381923()
USER32! 7e37b317()
USER32! 7e3778d0()
NTDLL! 7c91e473()
USER32! 7e369402()
USER32! 7e377611()
USER32! 7e3749c4()
USER32! 7e38a956()
USER32! 7e38a2bc()
USER32! 7e3b63fd()
USER32! 7e3b64a2()
USER32! 7e3a0877()
USER32! 7e3a082f()
__crtMessageBoxA(const char * 0x0012b198, const char * 0x004d5bfc `string', unsigned int 73746) line 65 CrtMessageWindow(int 2, const char * 0x004d5198 `string', const char * 0x0012c2cc, const char * 0x00000000, const char * 0x0012e2f0) line 520 + 22 bytes _CrtDbgReport(int 2, const char * 0x004d5198 `string', int 1044, const char * 0x00000000, const char * 0x004d52b4 `string') line 419 + 76 bytes
_free_dbg_lk(void * 0x00e41858, int 1) line 1044 + 40 bytes
_free_dbg(void * 0x00e41858, int 1) line 1001 + 13 bytes
free(void * 0x00e41858) line 956 + 11 bytes
l_alloc(void * 0x00000000, void * 0x00e41858, unsigned int 32, unsigned int 0) line 631 + 9 bytes luaM_realloc_(lua_State * 0x009a4d08, void * 0x00e41858, unsigned int 32, unsigned int 0) line 79 + 27 bytes
luaH_free(lua_State * 0x009a4d08, Table * 0x00cb4560) line 376 + 39 bytes
freeobj(lua_State * 0x009a4d08, GCObject * 0x00cb4560) line 383 + 13 bytes
sweeplist(lua_State * 0x009a4d08, GCObject * * 0x009a4d9c, unsigned int 4294967289) line 424 + 13 bytes
luaC_freeall(lua_State * 0x009a4d08) line 487 + 18 bytes
close_state(lua_State * 0x009a4d08) line 108 + 9 bytes
lua_close(lua_State * 0x009a4d08) line 212 + 9 bytes
CLuaDialogDlg::OnDo() line 224 + 9 bytes

After setting a breakpoint into CrtMessageWindow I could fetch the message

"Debug Assertion Failed!

Program: D:\MYPROJECTS\LuaDialog2\LuaDialog\Debug\LuaDialog.exe
File: dbgheap.c
Line: 1044

Expression: _CrtIsValidHeapPointer(pUserData)

So this looks to me, as if free is called with an invalid pointer, but there must be more memory corrupted, because the error message newer gets displayed.

Im using lua-5.1.4 from the source-tar statically linked, every other lib or dll is loaded via package from LuaForWindows_v5.1.4-30
Can you give me any helpfull hints, how to fix (or avoid) the problem?