opaque pointers and metatype
- From: Cosmin Apreutesei <cosmin.apreutesei@xxxxxxxxx>
- To: luajit@xxxxxxxxxxxxx
- Date: Sun, 2 Mar 2014 04:39:28 +0200
Hi,
What do you guys do when you have to use metatype on opaque pointers?
Take the following example:
struct OpaqueStruct * handle;
The constructor and destructor for OpaqueStruct are defined as:
void create(handle*);
void destroy(handle*);
Other functions are defined as func(handle, ...) -- so without the "*".
To use metatype I have to write metatype("struct OpaqueStruct",
{__index = ...}), so that my cdata type is "OpaqueStruct*", aka
"handle".
The create/destroy wrappers thus are:
function create()
h = ffi.new('handle[1]')
create(h)
return h[0]
end
function destroy()
h = ffi.new('handle[1]')
destroy(h)
end
Well, it seems ironic that I have to alloc memory to destroy a handle.
Am I going wrong with this approach? Are there better styles to wrap
these types of APIs? (incidentally, I'm illustrating the pthreads API)
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