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[Frama-c-discuss] EVA: understanding behaviors for undefined functions

Hi Virgile,

On Thu, Jan 12, 2017 at 12:52 AM, Virgile Prevosto <virgile.prevosto at
> wrote:

> Hello,
> 2017-01-12 0:48 GMT+01:00 Faraz Hussain <fh.faraz.hussain at>:
> >> available in a corresponding *.c file in the same directory. In order
> >> to use such a definition (as opposed to a specification), you have to
> >> add the .c file to the list of source files that have to be parsed on
> > Thank you very much!   Adding the implementation for fabsf inside
> wrong25.c
> > made the warning go away.  It also removed the following warning, that
> was
> > related to the same function:
> >
> > /mnt/local/csmith/runtime/safe_math.h:959:[value] warning: non-finite
> float
> > value.
> >                  assert \is_finite(tmp);
> >                  (tmp from fabsf(0.5f * sf1 + 0.5f * sf2))
> That's normal. As long as fabsf was neither defined nor specified, EVA
> did assume that it could return infinity or nan, and complained as
> soon as its result was used. Now that you have a definition, EVA can
> see that the returned value is finite.

Ah, yes. That makes sense. Thanks.

> >
> >
> > However, I do not want to have to add the implementation to all the files
> > individually.  But, adding it to math.c did not work. Is this because
> > frama-c now has to be rebuilt?  How do I rebuild, considering that I had
> > originally installed it using the OPAM based method ?
> >
> No, Frama-C does not need to be rebuilt (note however that you might
> want to put your own definitions in another file in order to prevent
> issues if you update Frama-C at some point).
> As mentioned above, if you want to use the definitions of math.c, you
> have to tell Frama-C to parse math.c in addition to wrong25.c, i.e.
> your command line should be of the form
>   frama-c wrong25.c $(frama-c -print-share-path)/libc/math.c [other
> options]
> wrong25.c has #include directive for the headers, but of course not
> for the corresponding implementations, hence they have to be added
> explicitly whenever they are needed.

Thank you, this is  a much cleaner solution indeed!  I actually used
`frama-c [my options] wrong25.c  mymath.c`, with options preceding the
files. Here, mymath.c contains my implementation of the required functions
(and includes math.h).

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