Re: [O] babel C, C++, D enhancement

[Thierry Banel]

Thanks Achim for finding and fixing this bug.

I do agree about fuzziness between int and float.
My Emacs considers
  2305843009213693951 as an integer,
  2305843009213693952 too large to be an integer.
My C++ compiler sees
  4294967295 as an integer,
  4294967296 as too large to fit an int.

So Babel C++ may cause problem for large integers.
I am not sure how we can fix this in any case.
In the meantime, we can force large values to be declared as doubles by
adding dot zero
like this:

#+BEGIN_SRC C++ :var large=9876543210 .0
printf ("%g", large);
#+END_SRC

Thierry


Le 13/06/2014 08:51, Achim Gratz a écrit :
> Eric Schulte writes:
>> This new patch looks great, and the test suite passes locally.  I've
>> just applied it.
> You also get a warning from the byte-compiler on something that is
> clearly a bug.  I think the fix should be:
>
> --8<---------------cut here---------------start------------->8---
> diff --git a/lisp/ob-C.el b/lisp/ob-C.el
> index dd03fa7..a794e2a 100644
> --- a/lisp/ob-C.el
> +++ b/lisp/ob-C.el
> @@ -264,7 +264,7 @@ (defun org-babel-C-val-to-C-type (val)
>            (list
>             (if (equal org-babel-c-variant 'd) "string" "const char*")
>             "\"%s\""))
> -         (t (error "unknown type %S" type)))))
> +         (t (error "unknown type %S" basetype)))))
>      (cond
>       ((integerp val) type) ;; an integer declared in the #+begin_src line
>       ((floatp val) type) ;; a numeric declared in the #+begin_src line
> --8<---------------cut here---------------end--------------->8---
>
> The type determination is a tad optimistic, too.  An Emacs integer may
> or may not fit into C type "int" depending on how Emacs is compiled and
> which compiler you are using.
>
>
> Regards,
> Achim.