Please CC (carbon copy not compiler!) me in any reply as I'm not subscribed -
thanks.
I've recently moved from G++ 3.3.1 to 3.4.1 and now 3.4.3
I have a suite of software which uses shared memory quite extensively and had
built up a class library which in outline does the following:
class shm_seg {
private:
void *base;
// Other goodies
public:
// Constructors and such
template<typename T> T* shm_cast(size_t offset)
{ return reinterpret_cast<T*>(etc etc); }
};
This is so I can put (given an offset in the shared memory to a "foo" in
segment described by "bar")
shm_seg bar;
// .... stuff
foo *fp = bar.shm_cast<foo>(foooffset);
Many versions of C++ including earlier versions of g++ required a "template
qualifer" so that the parser didn't get confused as defined in Stroustrup
appendix C 13.6 thus
foo *fp = bar.template shm_cast<foo>(foooffset);
G++ 3.3.* accepts this without warning. It also accepts the other version
without the "template" keyword.
G++ 3.4.* rejects the latter form with
error: `template' (as a disambiguator) is only allowed within templates
I agree that it's much better that the compiler figures out what I want
without me having to spell it out with spurious-looking "template"s
everywhere but wouldn't it be better if this was a "warning" not an "error"
to let people phase it out gently? Stroustrup doesn't actually say this only
has to be done in a template and in principle you can see why many compilers
aren't up to the task.
I know I can put "define template_qualifier" either to null or "template" as
required but this is 73K lines of code with a goodly percentage of those
"#ifdef obscure_machine_937" already.
(I wish I could leave out the "<foo>" too but that would mean that the result
type would have to be considered).
--
John Collins Xi Software Ltd www.xisl.com
