[Mono-list] accessing struct instance from managed code

[Nigel Benns]

Thanks again for this Managed -> Unmanaged info.

I understand after looking into it a little more, and the wrapper code is
so easy to do...

Half the point of .Net is the portability, so mangling some code and
making it platform specific defeats the purpose AFAIC.


> On Mon, 2005-02-28 at 08:16 -0500, Nigel Benns wrote:
>> yeah... its basically a GTK+ type of idea.
>
> Then see how Gtk# does things. :-)
>
>> The structure is for ewl_window
>> and ewl windows' struct has an EVAS object in it that i can access as
>>
>> window->evas;
>>
>> So basically I should wrap this a getter function from C# and make a C
>> function that returns the evas addr like this then:
>>
>> int *ewl_window_evas_get(Ewl_Window *win) {
>>
>>    return win->evas;
>>
>> };
>>
>> This is kindof what I wanted to avoid if possible, but if its going to
>> cause a whole bunch of Managed -> Unmanaged speghetti any other way,
>> then
>> I would rather do it this way. :)
>
> Native wrapper code can be avoided, if you're willing to make a great
> number of assumptions, including: compiler structure layout (such as
> padding), member sizes, and platform portability (a.k.a. 64-bit clean?).
>
> For example, if a structure contains a "size_t" member, then the size of
> that member will vary between 32-bit and 64-bit platforms, so a pure
> managed solution would either be: (a) tied to a particular platform, or
> (b) insanely ugly as you'd have to have lots of conditional code to
> determine whether you're reading a 32-bit or a 64-bit integer.
>
> It can be done, but it would be ugly.  Wrapper code is likely far easier
> to maintain.
>
>  - Jon
>
>
>