[Bug c/65158] printf attribute error reporting assumes single-byte characters

[manu at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65158

Manuel López-Ibáñez <manu at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |dmalcolm at gcc dot gnu.org,
                   |                            |manu at gcc dot gnu.org

--- Comment #3 from Manuel López-Ibáñez <manu at gcc dot gnu.org> ---
void foo(void) {
    __builtin_printf("%ñ%中");
    __builtin_printf ("%\x1B$B"); /* Taken from PR33748 */
 }

<source>: In function 'void foo()':
<source>:2:22: warning: unknown conversion type character '\xc3' in format
[-Wformat=]
2 |     __builtin_printf("%ñ%中");
  |                      ^~~~~~~~~
<source>:2:22: warning: unknown conversion type character '\xe4' in format
[-Wformat=]
<source>:3:23: warning: unknown conversion type character '\x1b' in format
[-Wformat=]
3 |     __builtin_printf ("%\x1B$B");
  |                       ^~~~~~~~~

Note that ñ and 中 are multi-byte but the message only shows one byte.

Another bug is that the location info fails to point within the format string
(ccing David):

void foo(int i) {
     __builtin_printf("%i%i%i%i%í%i%i",i,i,i,i,i,i);
    }

<source>:2:23: warning: unknown conversion type character '\xc3' in format
[-Wformat=]
2 |      __builtin_printf("%i%i%i%i%í%i%i",i,i,i,i,i,i);
  |                       ^~~~~~~~~~~~~~~~~