--- layout: fc_discuss_archives title: Message 3 from Frama-C-discuss on August 2017 ---
Hello, 2017-08-04 1:53 GMT+02:00 Yifan Lu <me at yifanlu.com>: > It appears that if I remove the const > > extern int * const globalx; > extern int * const globaly; > > I can use -wp-model ref and all is well... > > but I ran into another problem > > /*@ predicate something(int *x) = \true; */ > > /*@ requires something(x); */ > int test7(int *x); > > /*@ requires *x == 5; > @*/ > int test6(int *x) { > //@ assert *x == 5; > test7(x); > //@ assert *x == 5; > return 0; > } > > The second assertion cannot be proved. If I remove the predicate, it > works. Is this a bug? Could you provide the exact file and command line that you used to obtain this result? The second assert should not be provable (unless the call to test7 is guaranteed to never return successfully, in which case the code below the call is dead and any assertion on it holds) as long as there is no assigns for test7. In fact, Frama-C should have emitted a warning on a missing assigns clause. The kernel generates a clause based on the prototype of test7, which is absolutely not guaranteed to be sound and must at least be carefully reviewed. In the case at hand, as test7 takes a pointer as argument, Frama-C assumes that *x may be assigned by test7. Hence, no hypothesis on the content of *x after the call can be made. Best regards, -- E tutto per oggi, a la prossima volta Virgile