Hello gods of FFI and of the vm,

I am blocked for a while in the development of Smallapack (Smalltalk interface 
to LAPACK) on squeak.

I have a very strange behaviour isolated on a small test case (see below):

I want to call DLANGE, a LAPACK FORTRAN routine to compute the norm of a 
matrix.

And on the seventh call, i always get a stange result (result is 0.0 but will 
answer false to = 0.0).

This fail on unix with image 3.9alpha7029,
vm is: squeak -version
3.7-7 #1 Sat Mar 19 13:12:20 PST 2005 gcc 3.3.5
Squeak3.7 of '4 September 2004' [latest update: #5989]
Linux squeak.hpl.hp.com 2.4.27-1-386 #1 Fri Sep 3 06:24:46 UTC 2004 i686 
GNU/Linux
default plugin location: /usr/local/lib/squeak/3.7-7/*.so

Same code seem to work on windows (i have tried it today)...

Beware, i presume this can corrupt your image.
Maybe i am doing something wrong, could someone explain me please ?

Nicolas

----------------------------------------------------------------------------------------------------

My definition of dlange2.c (translated with f2c then modified to simply answer 
0.0) is:

 /* #include "f2c.h" */
 typedef double doublereal;
 typedef long integer;
 typedef long ftnlen;
 /*<       DOUBLE PRECISION FUNCTION DLANGE( NORM, M, N, A, LDA, WORK ) >*/
 doublereal dlange2_(char *norm, integer *m, integer *n, doublereal *a,
  integer *lda, doublereal *work, ftnlen norm_len)
 {
         return 0.0;
 } /* dlange2_ */

you just compile with:

 gcc -c dlange2.c; ld -shared -o libdlange2.so dlange2.o

and call from Squeak with:

ExternalLibrary subclass: #DLANGE2Library
 instanceVariableNames: ''
 classVariableNames: ''
 poolDictionaries: ''
 category: 'Smallapack-Test-DLANGE'

DLANGE2Library class>>moduleName
 ^'dlange2'

DLANGE2Library>>dlange2Withnorm: norm m: m n: n a: a lda: lda work: work 
length: lengthOfnorm 
 <cdecl: double 'dlange2_'( char * long * long * double * long * double * 
long )>
 ^self externalCallFailed

DLANGE2Library class>>testDLANGE2
 "DLANGE2Library testDLANGE2"
 
 | a m n lda norm cm cn clda work |
 m := lda := 3.
 n := 4.
 a := ExternalData
  fromHandle: (ByteArray new: m*n*8)
  type: ExternalType double.

 "AS FORTRAN IS PASSING POINTERS, DO ALLOCATE ExternalData"
 cm := ExternalData
  fromHandle: ((ByteArray new: 4) signedLongAt: 1 put: m; yourself)
  type: ExternalType long.
 cn := ExternalData
  fromHandle: ((ByteArray new: 4) signedLongAt: 1 put: n; yourself)
  type: ExternalType long.
 clda := ExternalData
  fromHandle: ((ByteArray new: 4) signedLongAt: 1 put: lda; yourself)
  type: ExternalType long.
 norm := 'M'.
 work := nil.
 ^(1 to: 10) collect: [:i | (self new
  dlange2Withnorm: norm m: cm n: cn a: a lda: clda work: work length: 1)
   = 0.0]

"you always obtain false from the seventh entry on..."