[Lazarus] SEGFAULT: difference between pointer and dynarray?

[leledumbo]

Sorry, I think I was too fast in reading the unit. After reading slowly, the
APIs actually uses open array, not dynamic array. In this case @lib should
be the same as @lib[0], but here's something interesting: I tried your code
(converted as program):

uses
  lua52;
type
  TluaLReg = array of luaL_Reg;
var
  LUA: Plua_State;
  lib : array of luaL_Reg;
  //lib : PluaL_Reg;
  i: Integer;

function l_dat_upd(LUA: Plua_State): LongInt; cdecl;
begin
end;

function l_dat_clr(LUA: Plua_State): LongInt; cdecl;
begin
end;

begin
LUA := luaL_newstate();
luaL_openlibs(LUA);
SetLength(lib, 2);
//SetLength(TluaLReg(lib), 2);
lib[0].name := 'update';
lib[0].func := @l_dat_upd;
lib[1].name := 'clear';
lib[1].func := @l_dat_clr;
writeln('actual = $'+HexStr(ptruint(@lib),8));
luaL_newlib(LUA, lib);
lua_setglobal(LUA, 'data');
lua_close(LUA);
end.

inserting some writelns in lua52 unit near problematic functions and running
in gdb results in:

luaL_newlib oa = $BFFFEE30
luaL_setfuncs oa = $BFFFECC0

Program received signal SIGSEGV, Segmentation fault.
0xb7e386d2 in ?? () from /lib/i386-linux-gnu/libc.so.6
(gdb) bt
#0  0xb7e386d2 in ?? () from /lib/i386-linux-gnu/libc.so.6
#1  0xb7fa2d12 in ?? () from /usr/lib/i386-linux-gnu/liblua5.2.so.0
#2  0xb7f95f09 in lua_setfield () from
/usr/lib/i386-linux-gnu/liblua5.2.so.0
#3  0xb7fa9a9a in luaL_setfuncs () from
/usr/lib/i386-linux-gnu/liblua5.2.so.0
#4  0x08066821 in LUAL_SETFUNCS (L=0x8071008, LR=..., highLR=1, NUP=0) at
lua52.pas:835
#5  0x080669e4 in LUAL_NEWLIB (L=0x8071008, LR=..., highLR=1) at
lua52.pas:859
#6  0x0804a3ea in main () at test.pas:31

As you can see, the pointer changes when you pass an open array into another
function expecting open array, even when static array is used (I've tried
that one too). So, somebody with enough compiler knowledge should analyze
this. Maybe you should create a bug report.



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