Function luaL_checkudata

Source/Misc/lua/src/lua.c:10336–10349

LUALIB_API void *luaL_checkudata (lua_State *L, int ud, const char *tname) {
void *p = lua_touserdata(L, ud);
if (p != NULL) {  /* value is a userdata? */
if (lua_getmetatable(L, ud)) {  /* does it have a metatable? */
lua_getfield(L, LUA_REGISTRYINDEX, tname);  /* get correct metatable */
if (lua_rawequal(L, -1, -2)) {  /* does it have the correct mt? */
lua_pop(L, 2);  /* remove both metatables */
return p;
}
}
}
luaL_typerror(L, ud, tname);  /* else error */
return NULL;  /* to avoid warnings */
}


LUALIB_API void luaL_checkstack (lua_State *L, int space, const char *mes) {