On 26-04-2012 00:06, David Nadlinger wrote:
On Wednesday, 25 April 2012 at 21:27:30 UTC, Jonathan M Davis wrote:
But you can't convert a delegate to a function without passing the
delegate to
the function one way or another, because the function doesn't have a
context
(not being a delegate).
That's the whole point of the question - you _can_ pull this off if you
create a small code fragment somewhere in memory which calls the
delegate with that specific context argument, and then set your function
pointer to its address (similar to thunks in most vtable implementations
or SEH, if you are familiar with these). Now, the only problem is that
executing data is not quite easy, mostly because of security mechanisms
(W^X, NX and friends).
As for the original question, I didn't need the feature so far (many C
libraries provide a void* bit of data to use at the client's
discretion), but if you need inspiration on how to implement it, I'd
look at projects like Mono and FFI libraries which likely need to
provide similar functionality.
Would probably be a good addition to Phobos.
David
libffi can do it. There's a reason I wanted std.ffi. ;) (Unfortunately
interest in such a module seemed low earlier.)
--
- Alex
