>> Also the old standard seems to require that ios_base::fixed |
>> ios_base::scientific (or any other combination) falls through to the
>> uppercase test; I was trying to use abi_tag for a solution as not only
>> would two versions of _S_format_float be necessary, but also num_get
>> due to the pre-instantiated templates for and , which
>> led me to http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60642. It might
>> just be more trouble than it's worth.
>
> I don't think we need to worry about that, if I understand correctly
> the combination of fixed|scientific has unspecified behaviour in
> C++03, so we can make our implementation do exactly what it does in
> C++11.
It seems to me that it is well defined, going from [lib.facet.num.put.virtuals]
> 6 All tables used in describing stage 1 are ordered. That is, the first line
> whose condition is true applies.
> A line without a condition is the default behavior when none of the earlier
> lines apply.
So fixed|scientific would be equivalent to specifying neither
according to table 58, and the resulting specifier would be %g or %G
depending on whether uppercase is set or not.
