Re: Problem with userdata (metatable)

["Goran Zoricic" <goran-gdalgs@...>]

I'm not a seasoned Lua veteran (yet ;) ),  but shouldn't you use:

lua_setmetatable(L, -2);

instead of:

...
lua_pushliteral(L, "__metatable");
lua_pushvalue(L, -3);
lua_rawset(L, -3);
...

Cheers,

Goran.

Anders Bergh wrote:
> Hi!
>
> I'm using Lua 5.1 and I've been trying to add my own userdata type. It
> works except I couldn't get methods working. I've been reading the
> chapter in the first edition of pil and
> http://lua-users.org/wiki/UserDataWithPointerExample.
>
> Here's the code I use:
>
> static const luaL_reg llua_user_f[] = {
>  /* Functions */
>  {"FindByNick", llua_user_FindByNick},
>
>  /* Methods */
>  {"GetNick", llua_user_GetNick},
>  {NULL, NULL}
> };
>
> /* Metatable */
> static const luaL_reg llua_user_m[] = {
>  {"__tostring", llua_user_tostring},
>  {NULL, NULL}
> };
>
> int lluaopen_user (lua_State *L) {
>  luaL_openlib(L, "user", llua_user_f, 0);
>  luaL_newmetatable(L, TYPE);
>  luaL_openlib(L, 0, llua_user_m, 0); /* mt */
>
>  lua_pushliteral(L, "__index");
>  lua_pushvalue(L, -3);
>  lua_rawset(L, -3);
>
>  lua_pushliteral(L, "__metatable");
>  lua_pushvalue(L, -3);
>  lua_rawset(L, -3);
>
>  lua_pop(L, 1);
>  return 1;
> }
>
> When I use "user:GetNick()" in Lua, I get the error: attempt to index
> field '?' (a nil value).
>
> getmetatable(user) returns nil, tostring(user) returns "user:
> 0x815598c". What exactly am I doing wrong?
>
> Anders

--
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