[squeak-dev] Passing array of float from Squeak to C

Joshua Gargus schwa at fastmail.us
Mon Feb 23 18:52:37 UTC 2009

You would pass in a ByteArray.  You can populate the ByteArray like this:

ba := ByteArray new: 8 * 3.  "3 is number of elements"
useBigEndian := true.  "or false, depending on what kind of machine you
are on"
ba doubleAt: 1 put: 1.0 bigEndian: useBigEndian.
ba doubleAt: 9 put: 4.55555555 bigEndian: useBigEndian.
ba doubleAt: 17 put: 3.0001 bigEndian: useBigEndian.
someObj primitiveDoSomethingWithDoubles: ba

Your primitive would need to get a pointer to the actual data in the
ByteArray (see senders of #firstIndexableField:), and cast it to (double*).

Hope this helps,

Ang Beepeng wrote:
> I am writing a plugin. How do I pass
> starray := {1.0.  4.5555555. 3.0001.}.
> to
> double * carray.
> Thanks.
> Ang Beepeng

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