RE: let binding with c

...sorry Manuel, a carriage-return missed when I copied my screen.

The result of the program execution is really :

dataOK1 = 12346789-123456789-123456789-, len is: 30

dataOK2 = 12346789-123456789-123456789-, len is: 30

data-not-KO = 1234, len is: 30



Also, notice that if I compile the same code with bigloo-3.1 , then it works. The trace becomes

dataOK1 = 12346789-123456789-123456789-, len is: 30

dataOK2 = 12346789-123456789-123456789-, len is: 30

data-not-KO = 12346789-123456789-123456789-, len is: 30

(.... data-not-KO becomes OK indeed, as we expected)



Regards,

Michel







-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Bruant, Michel
Sent: Friday, October 21, 2016 4:40 PM
To: [email protected]
Cc: [email protected]
Subject: RE: [bigloo] let binding with c



Hi Manuel,



You can compile the files I copy/paste in the email, below  =  "bigloo -c failc.c ;   bigloo fail.scm failc.o -o toto"

Then execute, and see the result:

> toto

dataOK1 = 12346789-123456789-123456789-, len is: 30

dataOK2 = 12346789-123456789-123456789-, len is: 30 data-not-KO = 1234, len is: 30



Let me comment:

- we have a C structure, a kind of buffer with 2 fields 'data' and 'length'

And we have a C function that set 'data' to a buf (filled) in the global area, and set 'len' to 30.

In the scheme part, we construct an instance of  c-struct and call the c-function that initialize  it; in a  'let*'

then, we try to retrieve the data content in the scheme, thanks to 3 bindings,  corresponding to 3 trials.

I would expect 3 identical  results. I can't explain why the latest trial is not ok.

It looks like the 'if' says 'true' in the 3rd binding , but we expect 'false' that leads to a correct bind of the data.

...at the same time , a similar 'if' in the 2nd binding works fine ... that's even more strange.



Tell me if you need more info.

Thanks, regards,

Michel









::::::::::::::

fail.h

::::::::::::::



typedef struct {

  int len;

  char* data;

} c_struct;



::::::::::::::

fail.scm

::::::::::::::

(module main

        (main main)

        (extern

         (include "fail.h")

         (type c_struct

               (struct (len::int "len")

                       (data::string "data"))

               "c_struct")

         (c_fill_struct::int (c_struct*) "c_fill_struct"))

        )



(define (main argv)

  (let ((my-struct     (c_struct* 0 "old")))

    (process my-struct)))



(define (process my-struct)

   (let* ((my-struct  (c_struct* -1 "init-content"))

          (res        (c_fill_struct my-struct))

          (dataOK1    (pragma::bstring "string_to_bstring_len( $1, $2 )" (c_struct*-data my-struct)  (c_struct*-len my-struct)))

          (dataOK2    (if (equal? (c_struct*-len my-struct) 999)

                                "we should not get this because -len is not 999"

                                (pragma::bstring "string_to_bstring_len( $1, $2 )" (c_struct*-data my-struct)  (c_struct*-len my-struct))))

          (data-not-KO     (if (equal? (c_struct*-len my-struct) 999)

                                (c_struct*-data my-struct) ;; we should not get this, ...but it looks we get it !!

                                (pragma::bstring "string_to_bstring_len( $1, $2 )" (c_struct*-data my-struct)  (c_struct*-len my-struct))))

          )



    (print "dataOK1 = " dataOK1 ", len is: " (c_struct*-len my-struct) )

    (print "dataOK2 = " dataOK2 ", len is: " (c_struct*-len my-struct) )

    (print "data-not-KO = " data-not-KO ", len is: " (c_struct*-len my-struct) )

   ))



::::::::::::::

failc.c

::::::::::::::

#include <stdlib.h>

#include "./fail.h"





char buf[100] = "123456789-123456789-123456789-zzzzzz.....";



int c_fill_struct (c_struct * my_c_struct) {

  buf[4] = 0;



  // return 'buf' , declare 30 bytes are significant,

  my_c_struct->len = 30 ;

  my_c_struct->data = buf;

  return 0;



}





-----Original Message-----

From: [email protected]<mailto:[email protected]> [mailto:[email protected]]

Sent: Friday, October 21, 2016 8:43 AM

To: Bruant, Michel

Cc: [email protected]<mailto:[email protected]>

Subject: RE: [bigloo] let binding with c



> If few lines can illustrate it, then that may be manageable.

Yes. That will help a lot.



Thanks in advance,



--

Manuel