[Help-smalltalk] Re: Questions regarding CArray's

[Paolo Bonzini]

On 10/16/2010 09:29 PM, Holger Hans Peter Freyther wrote:
> Hi,
>
> for a test case I would like to create a C Array.
>
> I want to do something like:
> (#(1 2 3) asByteArray asCObject: (CArrayCType from: #byte)) at: 0
>
> so somehow my CArrayCType from: #byte is wrong. I should be able to find the
> equivalent of<declaration: #( #(#name #array 3))>, if you lack the time I am
> going to search more and will find the solution myself.

First of all, I should point out that #asCData: mallocs a block that 
contains the _whole_ ByteArray.

Given this, I suggest you don't use CArrayCType, because a CObject is a 
pointer and there is very little difference between:

1) a pointer to the first byte:

   #[1 2 3] asCData: CByteType

2) a pointer to a 3-byte array:

   #[1 2 3] asCData: (CByteType arrayType: 3)

I suggest using the former, for which I added a shortcut #asCData in 
git, together with a similar shortcut for Strings: ('123' asCData) is 
the same as ('123' asCData: CCharType).

Alternatively,

  #[1 2 3] castTo: CByteType

creates the same thing, but backed by GC memory and with range checking.

Paolo