Joaquín,
Actually I tried to simplify into a test case a code in a real application I was debugging, but I forgot to put a line in it:
using boost::format;
format f("%0s%-32.32s:%|40t|%|.6|%|55t|%25s\n
");
f.bind_arg(1,"");
f % "test1" % 2.0 % "test3";
f % "test4" % 5.0 % "test6"; // calls clear() and breaks
It didn't call clear() explicitly, but operator%() automatically calls it to refresh to a new string. Your test does the same thing and is much clearer and simpler. I got a crash on your code too, when debugging on msvc 7.
I changed the offending line to:
if( bound_.size()==0 || (items_[i].argN_ >= 0) && !bound_[ items_[i].argN_ ] )
And now it is ok here!
Regards,
Edson Tadeu M. Manoel
On 5/24/06, Joaquín Mª López Muñoz <joaquin@tid.es> wrote:
Edson Tadeu ha escrito:
> If the format string have an absolute tabulation (%t), the
> basic_format::clear()
> method throws an access violation because of this piece code in
> format_implementation.hpp(138):
>
> if( bound_.size()==0 || !bound_[ items_[i].argN_ ] )
>
> Here items_[i].argN_ can be negative (defined in internals.hpp(70)),
> which
> is an invalid index to bound_[].
> I think a simple check of greather than zero would suffice to fix it.
> Here is a code that catches it:
>
> using boost::format;
> format f("%0s%-32.32s:%|40t|%|.6|%|55t|%25s\n");
> f % "test1" % 2.0 % "test3";
> f % "test4" % 5.0 % "test6"; // calls clear() and breaks
Hello Edson,
The test case you propose doesn't call clear() nor shows the error
you refer to: instead, a boost::io::too_many_args is thrown. Am I
missing something?
Anyway, seems like you spotted a real problem, and the following
does actually call bound_[ items_[i].argN_ ] with items_[i].argN_
negative inside basic_format::clear(), at least for the Boost.Format
code in the CVS trunk:
format f("%40t%1%");
int x=0;
f.bind_arg(1,x);
f.clear();
Can you also observe a crash with this snippet? If so, I can try to
propose and commit a fix following your suggestion of adding
a positiveness check in the offending if.
Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo
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