Bug#524064: Regression: compile failure on valid C++ code

[Alastair McKinstry <alastair.mckinstry@sceal.ie>]

Hi,

Ok. I'm not a C++ programmer, and would appreciate an explanation. The  
standalone code is:

#include <iostream>
#include <sstream>
#include <time.h>

using namespace std;

class DateTime {
public:
        DateTime();
        virtual ~DateTime() {}
        operator tm() const;
protected:
        long i;
};

class EpsBufr {
public:
                EpsBufr();
        virtual ~EpsBufr() {};
        void doit();
protected:
        DateTime base_;
};

DateTime::operator tm() const
{
        struct tm tm_date = tm();
        return tm_date;
}

void EpsBufr::doit() {

             ostringstream out;
             tm convert = base_;
             locale loc("");
             const std::time_put<char>& tfac =  
use_facet<time_put<char> >(loc);
             string format = "Forecast VT %A %e %B %Y %H UTC";
             tfac.put(out, out, ' ', &convert, format.c_str(),  
format.c_str()+format.length());
}


This compiles and works with g++ 4.1, and intel CC 11.  With g++-4.3  
(Debian 4.3.3-7) 4.3.3 I get the error:

test.cc: In member function ‘void EpsBufr::doit()’:
test.cc:38: error: invalid use of incomplete type ‘const struct  
std::time_put<char, std::ostreambuf_iterator<char,  
std::char_traits<char> > >’
/usr/include/c++/4.3/bits/localefwd.h:162: error: declaration of  
‘const struct std::time_put<char, std::ostreambuf_iterator<char,  
std::char_traits<char> > >’
/usr/include/c++/4.3/bits/locale_classes.tcc: In function ‘const  
_Facet& std::use_facet(const std::locale&) [with _Facet =  
std::time_put<char, std::ostreambuf_iterator<char,  
std::char_traits<char> > >]’:
test.cc:36:   instantiated from here
/usr/include/c++/4.3/bits/locale_classes.tcc:112: error: incomplete  
type ‘std::time_put<char, std::ostreambuf_iterator<char,  
std::char_traits<char> > >’ used in nested name specifier
/usr/include/c++/4.3/bits/locale_classes.tcc:117: error: cannot  
dynamic_cast ‘* *(__facets + ((unsigned int)(((unsigned int)__i) *  
4u)))’ (of type ‘const class std::locale::facet’) to type ‘const  
struct std::time_put<char, std::ostreambuf_iterator<char,  
std::char_traits<char> > >&’ (target is not pointer or reference to  
complete type)

I don't really understand the first line (Not really a C++ programmer)  
but why is it giving error messages about the standard includes?

An explanation would help: if g++ 4.3 is correct then good, and I'll  
file a report with Intel for compiling it!

Thanks
Alastair

On 14 Apr 2009, at 17:24, Bastian Blank wrote:

> tags 524064 moreinfo
> thanks
>
> On Tue, Apr 14, 2009 at 05:17:59PM +0100, Alastair McKinstry wrote:
> > Relevant code:
> > 196                 ostringstream out;
> > 197                 tm convert = base_;
> > 198             locale loc("");
> > 199             out.imbue(loc);
> > 200             const std::time_put<char>& tfac =  
> > use_facet<time_put<char> >(loc);
> > 201             string format = "Forecast VT %A %e %B %Y %H UTC";
> > 202             tfac.put(out, out, ' ', &convert, format.c_str(),  
> > format.c_str()+format.length());
>
> Please provide a _working_ (or failing) snippet which shows the
> behaviour. This one will be rejected by the compiler always, because  
> of
> missing includes and function body. Also please show why you think  
> this
> code is correct.
>
> > This code compiles fine with g++-4.1.
>
> gcc 4.3 got more strict for missing includes, so you need to show that
> it is not such a problem.
>
> Bastian
>
> --
> The more complex the mind, the greater the need for the simplicity  
> of play.
> 		-- Kirk, "Shore Leave", stardate 3025.8

Regards,
Alastair

--
Alastair McKinstry  , <alastair@sceal.ie>     http://blog.sceal.ie

Anyone who believes exponential growth can go on forever in a finite  
world
is either a madman or an economist - Kenneth Boulter, Economist.