[Pan-users] Pan compilation issues with clang++

[Rhialto]

In the context of the pkgsrc project (packaging software to compile it
with source) there recently was a bulk build using clang++ as a compiler
rather than g++.

This showed a few problems that g++ never complained about, but I'm
supposing for now that clang++ is correct in complaining.

First, where to look for log files:

http://ftp.netbsd.org/pub/pkgsrc/misc/joerg/20131216.1249/pan-0.139nb12/build.log
linked from
http://ftp.netbsd.org/pub/pkgsrc/misc/joerg/20131216.1249/meta/report.html

The first error is this one:


In file included from file-util.cc:38:
In file included from ./log.h:26:
/usr/include/c++/deque:912:49: error: invalid application of 'sizeof' to an 
incomplete type 'value_type' (aka 'pan::Log::Entry')
    static const difference_type __block_size = sizeof(value_type) < 256 ? 4096 
/ sizeof(value_type) : 16;
                                                ^~~~~~~~~~~~~~~~~~
/usr/include/c++/deque:1183:15: note: in instantiation of template class 
'std::__1::__deque_base<pan::Log::Entry, std::__1::allocator<pan::Log::Entry> 
>' requested here
    : private __deque_base<_Tp, _Allocator>
              ^
./log.h:52:27: note: in instantiation of template class 
'std::__1::deque<pan::Log::Entry, std::__1::allocator<pan::Log::Entry> >' 
requested here
        std::deque<Entry> messages;
                          ^
./log.h:49:14: note: definition of 'pan::Log::Entry' is not complete until the 
closing '}'
      struct Entry {
             ^

Corresponding source in general/log.h looks like

 44       /**
 45        * A log message specifying the message's text, severity, and time.
 46        * @see Log
 47        * @ingroup general
 48        */
 49       struct Entry {
 50         time_t date;
 51         Severity severity;
 52         std::deque<Entry> messages;
 53         std::string message;
 54         bool is_child;
 55         Entry() : is_child(false) { }
 56       };
 
It seems to me (I've never used clang myself) that the complaint is
about the std::deque<Entry> which is inside the struct Entry. And the
size of struct Entry isn't known until line 56.

I'm not sure what the C++ standard says about using incomplete types in
containers such as std::deque<> but I can imaging it is indeed not
allowed. And an Entry containing a deque of itself smells fishy anyway.

Now the big question is: what to do about it?

(and smaller question: how about the next errors in the log file? I
haven't checked if they are followup errors, or similar ones, or what)

-Olaf.
-- 
___ Olaf 'Rhialto' Seibert  -- The Doctor: No, 'eureka' is Greek for
\X/ rhialto/at/xs4all.nl    -- 'this bath is too hot.'

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