Re: Lua calling C question

[Asko Kauppi <asko.kauppi@...>]

If you mean allocating a buffer where the data is read (by C) and using 
it then in Lua, why not simply give a proper userdata block length (you 
can use a structure with 'data[0]' as a "growing tail" in most 
compilers).  Then, you'd attack __index metamethod to the userdata so 
it seems like a usual Lua (read-only) table to Lua scripts. Would this 
be enough?

Other alternative (since it's char*) would be pushing a specific length 
string, but this might need an interim buffer malloced/freed by you 
(since Lua strings are read-only).

Did I even touch close? :)

btw, Why is the iMaxSize a reference (you're using C++ here, right?). 
That is, is the 'Read' function actually setting/writing it, is it 
input only, or mixed input-output.  Please specify.

-ak

30.4.2005 kello 13:26, Robert Aronsson kirjoitti:

 Hi guys,
> Excuse me if this has been posted before but I cant find it in the 
> archives.
>
> I need to call a c function from lua that looks like this
>
> bool Read(char *pData,unsigned int &iMaxSize);
>
> The Read function will read some data of max iMaxSize and place it in
> the pre-allocated pData char pointer, returns true on success or false
> on failure.
>
> My question is, how do I pre-allocate an array in Lua that I can use
> to send into this C function? (without doing a for loop that adds
> strings to a variable for example)
>
> Best Regards,
> Robert Aronsson