[Bug libfortran/45323] warnings compiling libgfortran/io/write.c: array subscript has type 'char'

[fxcoudert at gcc dot gnu dot org]

------- Comment #2 from fxcoudert at gcc dot gnu dot org  2010-08-23 08:37 -------
(In reply to comment #1)
> That's the lines:
>   1472    char cup;
>   1467    size_t dim_i;
>   1504                cup = toupper (base_name[dim_i]);
>   1511            cup = toupper (obj->var_name[dim_i]);
> and
>   1743    char c;
>   1741    index_type i;
>   1760        c = toupper (dtp->namelist_name[i]);
> 
> (with: typedef ssize_t index_type;)
> 
> According to POSIX, toupper is defined as:
>        int toupper(int c);
> 

> I am not sure I understand the message itself:
>   "array subscript has type 'char'"
> because in those lines I do not see how the array subscript can be 'char'. It
> might be due to the way Tru64 Unix implements "toupper".

Typically happens because when toupper is a macro that is equivalent to
something like:

#define toupper(x) (upper_table[x])

POSIX seems to says "shall be declared as functions and may also be defined as
macros".

> Does it help to cast the argument to (int)? I mean:
> -                cup = toupper (base_name[dim_i]);
> +                cup = toupper ((int) base_name[dim_i]);
> for all three toupper?

It should. Another solution is to force the function call (but that may mean
slower code):

  cup = (toupper) (base_name[dim_i]);


-- 

fxcoudert at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |fxcoudert at gcc dot gnu dot
                   |                            |org
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2010-08-23 08:37:12
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45323