> I don't use any heuristic - the author of the patch appears to search the 
> file for non-printable character, see the isBinaryFile() function: 
> 
>  int isBinaryFile()
>  
>    /* look for non-printable chars */
>    for(i = 0; i < n; i++)
>      if (!isprint(buf[i]) && !isspace(buf[i]))
>        return(1);

This is broken as long as "isprint" doesn't have proper NLS support.
Even then it's arguable that you might print text files from other locales 
some times...


Martin