Re: [O] Problems running C code in org-mode under Windows - SOLVED

[Richard Stanton]

> One problem - when using bash as the shell, when trying to execute the
> compiled file, it tries to execute the empty file, not the file that was just
> compiled (which has the same name, but the extension .exe, added by the
> compiler).
> 
> A partial solution to this is to append ".exe" to the name of the binary temp
> file if running under Windows. E.g., start org-babel-C-execute something
> like this:
> 
> (defun org-babel-C-execute (body params)
>   "This function should only be called by `org-babel-execute:C'
> or `org-babel-execute:C++'."
>   (let* ((tmp-src-file (org-babel-temp-file
>                       "C-src-"
>                       (cond
>                        ((equal org-babel-c-variant 'c) ".c")
>                        ((equal org-babel-c-variant 'cpp) ".cpp"))))
>          (tmp-bin-file (org-babel-temp-file
>                       "C-bin-"
>                       (if (equal system-type 'windows-nt) ".exe" "")))
> 
> [...]
> 
> I say "partial solution" because the output in the org file is *still* blank, 
> but
> at least the program does get run this way...

Solved (approximately):

Here was the org file I was using:

#+begin_src C :includes <stdio.h>
    int a=2;
    int b=3;
    printf("%d\n", a+b);
#+end_src

This ran fine, but returned an error code of 2, which caused problems. When I 
added the extra line
 
   return(0);

at the end, it ran fine.

To allow for people who might be using the Cygwin bash shell in Emacs under 
Windows (which is recommended by many),  I do recommend making the change I 
suggested above, adding the following lines to ob-C.el:

>          (tmp-bin-file (org-babel-temp-file
>                       "C-bin-"
>                       (if (equal system-type 'windows-nt) ".exe" "")))
>

This prevents bash trying to run an (empty) file with no extension when the 
compiler has generated a file with a ".exe" extension. Otherwise, it looks like 
I now have this running fine. 

I also suggest not creating an empty binary file and just letting the compiler 
create it, unless this poses some risks I'm not seeing.

Thanks.