Re: Hooks for I/O, memory, etc?

[Terence Martin <tmartin@...>]

> Roberto Ierusalimschy wrote:
> > 
> > The drawback is that everyone using Lua would have to start it
> > with something like
> > 
> >   lua_open(&realloc);
> > 
> > which is not exactly friendly... 
> 
> Not really. Lua _open can do that behind our backs. 
> You keep the "callback functions"/"hooks" stored as 
> funcion pointers  somewhere in the Lua state. By default, 
> the state is set up by lua_open to use the default ANCI C 
> functions. The callback can then be changed by a new LUA api 
> call such has lua_set_callbacks(lua_state *, 
> lua_callback_struct *);

That won't work so good, because lua_open needs to allocate memory. It
would probably be quite catastrophic if some things were allocated
with malloc and some were allocated using your custom routines/

For this to work, there either has to be a call you make before
lua_open (which means having some global variables, which is perhaps
undesirable), or you have to tell lua_open yourself what functions to
use (which means extra paramters of some type, which is perhaps
undesirable).

I think maybe the first one might be a little cleaner looking, but I
don't really have a preference.