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[Frama-c-discuss] Assigns clause

It works perfectly with WP plugin: the fun spec is discharged thanks to Alt-Ergo .
But I have not tried with Jessie.
D.

De : frama-c-discuss-bounces at lists.gforge.inria.fr [mailto:frama-c-discuss-bounces at lists.gforge.inria.fr] De la part de Rovedy Aparecida Busquim e Silva
Envoy? : mercredi 25 septembre 2013 15:58
? : Frama-C public discussion
Cc : Nanci; Luciana Akemi
Objet : Re: [Frama-c-discuss] Assigns clause

Thank you for your reply.

We have tried to run the specification suggested, but it did not work, the GWhy GUI did not open. It showed the following message
[kernel] user error: syntax error while parsing annotation

After some attempts we figured out that the problem seems to be the requires clauses, because without them it runs.

We have searched some examples in the Jessie Tutorial (http://krakatoa.lri.fr/jessie.html) with requires clauses inside behaviors, but we have not found. We found an example in the reference manual of ACSL Version 1.4 and we tried to run it, but it did not work too.

We are using the Jessie plugin. Why requires clause inside behavior is not working? Is it possible to include requires clauses inside behavior in the Jessie plugin?

Best regards,
Nanci, Rovedy, Luciana

*/

// ######################################################
// Example of the reference manual of ACSL Version 1.4
/*@
  behavior p_changed:
  assumes n > 0;
  requires \valid (p);
  assigns *p;
  ensures *p == n;
  behavior q_changed:
  assumes n <= 0;
  requires \valid (q);
  assigns *q;
  ensures *q == n;
@ */

void f (int n, int *p, int *q)
{
  if (n > 0)
    *p = n;
  else
    *q = n;
}

2013/9/25 Pariente Dillon <Dillon.Pariente at dassault-aviation.com<mailto:Dillon.Pariente at dassault-aviation.com>>
Hi,

You may give a look to the ACSL reference manual, to the notions of behaviors/assumes.
The following is an example of what the Interp_Tab_1s spec could look like.

/*@

requires \valid (Ptr+(0 .. 1));
requires Itab == 0 || Itab == 1;

behavior Itab_false:
  assumes Itab != 1;
  requires \forall integer j; 0 <= j < 3 ==> \valid (Ptr[0]+ j);
  requires \valid (Interp+(0 .. 2));
  assigns Interp[0..2];
  ensures  \forall integer j; 0 <= j < 3 ==>
                \abs ((Interp[j]) - (*(Ptr[0]+ j))) < BOUND;

behavior Itab_true:
 assumes Itab == 1;
  requires \forall integer j; 0 <= j < 2 ==> \valid (Ptr[1]+ j);
  requires \valid (Interp+(0 .. 1));
  assigns Interp[0..1];
  ensures  \forall integer j; 0 <= j < 2 ==>
    \abs ((Interp[j]) - (*(Ptr[1]+ j))) < BOUND;

complete behaviors Itab_false,Itab_true;
disjoint behaviors Itab_false,Itab_true;

*/


HTH,
D.

De : frama-c-discuss-bounces at lists.gforge.inria.fr<mailto:frama-c-discuss-bounces at lists.gforge.inria.fr> [mailto:frama-c-discuss-bounces at lists.gforge.inria.fr<mailto:frama-c-discuss-bounces at lists.gforge.inria.fr>] De la part de Rovedy Aparecida Busquim e Silva
Envoy? : mardi 24 septembre 2013 21:54
? : Frama-C public discussion
Cc : Nanci; Luciana Akemi
Objet : [Frama-c-discuss] Assigns clause

Hi,

We have a doubt related to assigns clause.

All VCs of the attached function were proved.

We wrote an assigns clause to the Interp array taking in account three elements:
 assigns Interp[0..2];

However, we would like to write a more precise assigns clause for the Interp array that has two or three elements according to Itab value.

In the requires and ensures clauses the Itab value was considered, for example:
requires Itab != 1 ==> \valid_range (Interp,0,2);

requires Itab == 1 ==> \valid_range (Interp,0,1);

How to write the assigns clause for the Interp array taking in account the Itab value?

Best regards,
Nanci, Rovedy e Luciana

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