Hi Caio,
On Oct 24, 2010, at 11:09 AM, Caio Chassot wrote:
> On 2010-10-24, at 05:06 , Matt Aimonetti wrote:
>
> Is there any difference if I do these instead:
>
>> pointer = Pointer.new_with_type("f")
>
> p = Pointer.new(:float) #<= new instead of new_with_type
>
>> pointer.assign(3.2)
>
> p[0] = 3.2 #<= #[]= instead of #assign
>
>
> I have used both successfully in the past. Just wondering if I was just lucky
> or if they're fine.
They are the same :)
> Also, what's with the #[] thing anyway? What would I get using p[1], p[2]? Is
> this a way to deal with C arrays or otherwise do basic pointer arithmetics?
A Pointer object allows you to allocate memory of a given type for a given
number of elements. You can create an array of floats for example. Then, #[]
and #[]= make sense to get/set elements of this array.
Pointer objects are also returned by MacRuby when calling a native API that
returns a pointer to something. For example, float *. The API documentation
might state that it's one float, or an array of floats. In this case, MacRuby
doesn't really know much about the pointer itself (like its bounds), which is
why using #[] and #[]= must be done in a very careful way.
Laurent_______________________________________________
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