Re: [Pharo-users] [UFFI] Getting an array of opaque structures filled

[Julien Delplanque]

Thanks, it works I get an instance of FFIOpaqueObject.

But how do I get a specific  libusb_device object from the list?

Thanks again for you quick answer :-).

Julien

On 01/07/16 11:44, Esteban Lorenzano wrote:

Hi,

an opaque structure is not an FFIExternalObject but an FFIOpaqueObject.
in that case, something like (simplified):

ctx := (your context).
list := FFIOpaqueObject new.
size := self getDevice: ctx list: list.

getDevice: ctx list: list
        ^ self ffiCall: #(size_t libusb_get_device_list (libusb_context *ctx, 
FFIOpaqueObject ***list))

should work (note that of course you can make libusb_device an alias for your 
type… that does not matters much, this is just a simplification).

if this does not works, if you can provide me code to reproduce it, I can give 
it a shot and see what happens :)

Esteban

On 01 Jul 2016, at 11:19, Julien Delplanque <jul...@tamere.eu> wrote:

Hello everyone,

I have a question about the UFFI API. I have the following function:

ssize_t libusb_get_device_list (libusb_context *ctx, libusb_device ***list)

where libusb_device is an opaque structure.

I made a type mapping "ssize_t" -> "int" and an object inheriting
from FFIExternalObject for the "libusb_context" (others methods
using it are working).

I can not find how to get an array filled with libusb_device using UFFI from 
Pharo. :-(

Thanks in advance,

Julien