Re: deny table modification

[Philipp Kraus <philipp.kraus@...>]

Am 21.12.2012 um 08:55 schrieb Thijs Schreijer:

>> Hello,
>> 
>> I use from the C API a set of tables for storing function pointers in it.
>> On the Lua side, I can call the function from the table, but I would like
>> to deny any modification on the table from the Lua script.
> 
> To prevent modifications on the table (that is the table CONTENTS), you can
> use a proxy table, with some metamethods
> 
>> 
>> I use a luaL_newlib and a lua_setglobal for setting my function table, but
>> the script can set the global variable to nil or something else. Can I
>> deny this, so that the table can not be overwritten?
> 
> To prevent modifying the global that HOLDS the table itself, you could use a
> similar approach on the global table (_G, _ENV, and the likes). But that
> would have a penalty on all global lookups instead of just your table.

For my understanding, after reading the Lua documentation: The global table
is a "lookup table" for data in e special memory block? Will this memory block
be prevented for write access or can each Lua script modify items of this table?

Phil