Re: [cffi-devel] CFFI-USER: Dereferencing an address to a pointer array ... ? SOLVED!

[Frank Goenninger]

Well, one should pass the address of the pointer via

(cffi:pointer-address ... )

and everything is fine...

Frank


Am 17.11.2007 um 20:30 schrieb Frank Goenninger:

* PGP Signed: 11/17/07 at 20:30:52

Hi all:

I have in C  in a library:

typedef struct  __tsPMDevInfo
{
   ... some slots in here; don't matter ...

} tsPMDevInfo, *ptsPMDevInfoPtr;


// nFindPMs -- Find PM Devices on all available serials


int nFindPMs( ptsPMDevInfoPtr **pppsPMDevInfoArray,
                          int *pnNrPMsFound )
{
  int nRC = 0;

  ptsPMDevInfoPtr *ppsPMDevInfoArray = NULL;

 .... Here, memory gets allocated and
 ppsPMDevInfoArray points to an array of
pointers to struct tsPMDevInfo !

  if( pppsPMDevInfoArray != NULL )
    *pppsPMDevInfoArray = ppsPMDevInfoArray;

  if( pnNrPMsFound != NULL )
    *pnNrPMsFound = nNrPMs;

  if( nNrPMs > 0 )
    nRC = PMIO_RC_OK;
  else
    nRC = PMIO_RC_NO_PM_FOUND;

  return nRC;
}

In Lisp-land I do (simplified):

(defcfun ("nFindPMs" %nFindPMs) pmio-rc
  (ppsPMDevInfoPtr :pointer)
  (pnNrPMs         :pointer))

(defun find-pms (ppsPMDevInfoPtr pnNrPMs)
  (%nFindPMs ppsPMDevInfoPtr pnNrPMs))

I do get a valid value for the nr of PMs back with

(mem-ref pnNrPMs :int 0)



(mem-ref ppsPMDebInfoPtr :pointer 0)



Thx for any pointers ;-) !!!

Frank



* Frank Goenninger<[EMAIL PROTECTED]>
* 0xED320F02:0x05AE0907
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* PGP Signed: 11/17/07 at 20:30:52
* text/plain body
* Frank Goenninger<[EMAIL PROTECTED]>
* 0xED320F02:0x05AE0907

// ---------------------------------------------------------------------- -- // ---------------------------------------------------------------------- --- But I am unable to get a valid foreign pointer back for ppsPMDevInfoPtr : always returns an invalid value (no valid memory address). So, the question is: How do I return a pointer to an array of pointers ? In C land everything is OK and the pointer array is valid: check via ppsPMDebInfoPtr[0] -> This is the pointer to a valid struct tsPMDevInfo.

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