+/**
+ * \brief Like luaL_checkudata, with additional debug logs.
+ *
+ * This function is for debugging purposes only.
+ *
+ * \param L a lua state
+ * \param ud index of the userdata to check in the stack
+ * \param tname key of the metatable of this userdata in the registry
+ */
+void* sglua_checkudata_debug(lua_State* L, int ud, const char* tname)
+{
+ XBT_DEBUG("Checking the userdata: ud = %d", ud);
+ sglua_stack_dump("my_checkudata: ", L);
+ void* p = lua_touserdata(L, ud);
+ lua_getfield(L, LUA_REGISTRYINDEX, tname);
+ const void* correct_mt = lua_topointer(L, -1);
+
+ int has_mt = lua_getmetatable(L, ud);
+ XBT_DEBUG("Checking the userdata: has metatable ? %d", has_mt);
+ const void* actual_mt = NULL;
+ if (has_mt) {
+ actual_mt = lua_topointer(L, -1);
+ lua_pop(L, 1);
+ }
+ XBT_DEBUG("Checking the task's metatable: expected %p, found %p", correct_mt, actual_mt);
+ sglua_stack_dump("my_checkudata: ", L);
+
+ if (p == NULL || !lua_getmetatable(L, ud) || !lua_rawequal(L, -1, -2))
+ luaL_typerror(L, ud, tname);
+ lua_pop(L, 2);
+ return p;
+}
+