Hello, Sorry for the long winded questions...  I was wondering if someone could point me to any example example on how to set/get arrays in C from lisp ? I am using CFFI and Swig.  currently I have only primitive interface functions that pass pointers and floats.  I am thinking of three array cases. I&#39;m a bit of a beginner here, so please bear with me - the existing documentation is not completely clear (to me, as a lisp beginner :-)..<div>
<br><div><div><div><br></div><div>1)  the C function allocates an array (as a side effect) and passes back a pointer to array to lisp . I would later have to free memory for this array explicitly.</div><div><br></div><div>
2) the lisp function allocates an array and passes a pointer to the &quot;C&quot; function,  The C function modifies the array.  In this case lisp would be allocating the array.   Side question:  Do I need to use CFFI in lisp to allocate the array ? - or can this be done transparently by the lisp dynamic typing when the array variable is bound ?</div>
</div><div><br></div><div>3) I have several simple C functions that return smaller arrays (like [ x, y, z], where x,y,z = float or integer.).  Would be nice to be able to pass by value as a return value on the stack, but I am not sure how to handle this from C to lisp.  Example:  </div>
<div><br></div><div>C function:</div><div><br></div><div>Color getColorValue ( Image *image, x, y),  Where color is a array  triplet  [r, g, b],, could be floats or ints depending...</div><div><br></div><div>Desired lisp function:</div>
<div><br></div><div>(let ((color (get-color-value image x y))</div><div>   ; then do something with list &quot;color</div><div><br></div><div>4) unrelated question...maybe this should be posted to swig list (but i am not sure if there are any active CFFI users in that group).</div>
<div>Is there an easy way to automatically create lisp-style function names ?</div><div><br></div><div>For example:</div><div><br></div><div>swig generates:</div><div><br></div><div><div>(cffi:defcfun (&quot;frameHeight&quot; frameHeight) :int</div>
<div>  (frame :pointer))</div></div><div><br></div><div>I would like to generate translate the C function name to &quot;frame-height&quot; (to make it more of a lisp style).</div><div><br></div><div>I tried using</div><div>
<br></div><div>%rename frameHeight frame-height </div><div><br></div><div>in the swig. &quot;.i&quot; file template, but that doesn&#39;t seem to work.  The notes in the documentation on &quot;lispify&quot; I am not at the stage where I understand it.</div>
<div><br></div><div>I thought that some google searches would turn up some canonical examples or tutorials on this, but there are not many (except the curl example - and it makes me wonder how many people are actually using it :-)</div>
<div><br></div><div>thanks again,</div><div><br></div><div>K</div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div></div></div>