Support for %d$c format specifier in diagnostics.c

[Ishikawa]

Gabriel Dos Reis wrote:

> | Thank you for your previous comments.
> |
> | Supporting %d$s form format specifier
> 
> hugh.  what is that supposed to mean?

Hi, 

The support for positional argument specification in the
form of %d$c for diagnostic output routines 
was suggested by Zack Weinberg in

http://gcc.gnu.org/ml/gcc/2003-06/msg02458.html


> |  might take a few days more than I originally thought it would. 
> |
> | A potential Bug:
> |
> | As I dive through the code, I think I found a bug in
> | the original code.
> |
> | Original BUG (?) found.
> |  Near line 517 of diagnostic.c , "u" ought to be "o"';
> |        case 'o':
> |           if (wide)
> |             output_formatted_scalar
> |               (buffer, "%" HOST_WIDE_INT_PRINT "o",
> |                va_arg (*text->args_ptr, unsigned HOST_WIDE_INT));
> |           else
> |             output_integer_with_precision
> | Here --->      (buffer, *text->args_ptr, precision, unsigned, "u");
> |         break;
> 
> Yes, the "u" above should have been "o".  Thanks.

Great. I fixed my local copy, too.

> | This means that this feature of using precision of
> | %lu, and %llu as opposed to simple %u has not been used by
> | the diagnostic messages. [ Maybe I can forget about the precision :-) ]
> |
> | A question.
> |
> | Why are we using HOST_WIDE_INT ?
> 
> because the "w" in "%wo" is for HOST_WIDE_INT.  See
> 
>   http://gcc.gnu.org/ml/gcc-patches/2003-06/msg02548.html

Obviously, there are more things in the background than
I could glean from the code alone.

> | Well this is somewhat a rhetorical question.
> |
> | I can guess that on some hosts, the distinction of short, int, and
> | long is such that we need to go to long (instead of simple int) to
> | make sure that we get the the most wide natural size of int.
> |
> | In that case, we must use HOST_WIDE_INT_PRINT_DEC instead of simple
> | "%d" to print such data. diagnostic.c supports "%wd" as opposed to
> | "%d" for this type of intrinsic wide int.
> |
> | But what surprised me a little bit is this.
> | We already  support %d, %ld, and %lld in diagnostic.c.
> 
> that should not be a surprise: %wd is not a susbtitute for %ld, nor %lld.
> 
> | So my main question would be why do we support two different series of
> | enlarging the size of the types in diagnostic.c?
> 
> there were (still are?) places where we need to support at least %ld.
> %wd is for abstracting over the actual data type behind HOST_WIDE_INT.
> I think it also makes sense for uniformity to also support long long.

So I take this %wd thing is rather new. No *.po files contain
the %w string yet.

I will check the mentioned URL to see if I handled
the %w construct adequately.

Oh, I posted the patch to diagnostic.c to gcc-patches mailing list, 
but it can use some cleaning up, etc..


-- 
int main(void){int j=2003;/*(c)2003 cishikawa. */
char t[] ="<CI> @abcdefghijklmnopqrstuvwxyz.,\n\"";
char *i ="g>qtCIuqivb,gCwe\np@.ietCIuqi\"tqkvv is>dnamz";
while(*i)((j+=strchr(t,*i++)-(int)t),(j%=sizeof t-1),
(putchar(t[j])));return 0;}/* under GPL */