Re: [Cppcms-users] Compile error: traits is not a template

[陈抒 <csf...@gm...>]

json.h was added into group.h
groups.h include group.h

陈抒
Best regards
http://blog.csdn.net/sheismylife


On Sat, Sep 1, 2012 at 3:05 PM, 陈抒 <csf...@gm...> wrote:

> Thank you. But I see new error.
> groups.h file:
>
> #ifndef __GROUPS_H
> #define __GROUPS_H
>
> #include <vector>
> #include <boost/shared_ptr.hpp>
> #include "group.h"
>
> namespace kaimei{
>
>   class groups{
>   public:
>     typedef std::vector<boost::shared_ptr<group> >::iterator iterator;
>     typedef std::vector<boost::shared_ptr<group> >::const_iterator
> const_iterator;
>
>     void add(boost::shared_ptr<group> g);
>
>     bool empty() const;
>
>     unsigned int size() const;
>
>     std::string json_string() const;
>
>     friend class cppcms::json::traits<kaimei::groups>;
>
>    private:
>     std::vector<boost::shared_ptr<kaimei::group> > values_;
>   };
>
> }
>
> namespace cppcms {
>   namespace json {
>
>     template<>
>       struct traits<kaimei::groups> {
>
>       static void set(value &v, kaimei::groups const& in) {
> v.set("size", in.size());
>  v.set("values", in.values_);
>       }
>     };
>
>   }
> }
>
> #endif
>
>
> error message:
>   3%] Generating ../../src/view/welcome.cpp, ../../src/view/home.cpp,
> ../../src/view/gprs_message.cpp, ../../src/view/gprs_manager.cpp,
> ../../src/view/gprs_password.cpp, ../../src/view/gprs_log.cpp,
> ../../src/view/register_client.cpp, ../../src/view/gprsConfig.cpp,
> ../../src/view/login.cpp, ../../src/view/group_management.cpp
>  [  6%] Building CXX object bin/CMakeFiles/cppweb.dir/groups.cpp.o
> In file included from /home/chenshu/work/kaimei/cppweb/include/group.h:5:0,
>                  from /home/chenshu/work/kaimei/cppweb/include/groups.h:6,
>                  from /home/chenshu/work/kaimei/cppweb/src/groups.cpp:1:
> /usr/include/cppcms/json.h: In member function ‘void
> cppcms::json::value::set_value(const T&) [with T =
> boost::shared_ptr<kaimei::group>]’:
> /usr/include/cppcms/json.h:604:5:   instantiated from ‘static void
> cppcms::json::traits<std::vector<T> >::set(cppcms::json::value&, const
> std::vector<T>&) [with T = boost::shared_ptr<kaimei::group>]’
> /usr/include/cppcms/json.h:247:4:   instantiated from ‘void
> cppcms::json::value::set_value(const T&) [with T =
> std::vector<boost::shared_ptr<kaimei::group> >]’
> /usr/include/cppcms/json.h:316:4:   instantiated from
> ‘cppcms::json::value::value(const T&) [with T =
> std::vector<boost::shared_ptr<kaimei::group> >]’
> /usr/include/cppcms/json.h:352:4:   instantiated from ‘void
> cppcms::json::value::set(const char*, const T&) [with T =
> std::vector<boost::shared_ptr<kaimei::group> >]’
> /home/chenshu/work/kaimei/cppweb/include/groups.h:39:28:   instantiated
> from here
> /usr/include/cppcms/json.h:247:4: error: incomplete type
> ‘cppcms::json::traits<boost::shared_ptr<kaimei::group> >’ used in nested
> name specifier
> make[2]: *** [bin/CMakeFiles/cppweb.dir/groups.cpp.o] Error 1
> make[1]: *** [bin/CMakeFiles/cppweb.dir/all] Error 2
> make: *** [all] Error 2
>
>
> 陈抒
> Best regards
> http://blog.csdn.net/sheismylife
>
>
> On Sat, Sep 1, 2012 at 2:34 PM, Artyom Beilis <art...@ya...> wrote:
>
>> >
>>
>> >But I got error when compiling another class. It has group.h and
>> group.cpp file.
>> >
>> >
>> >#ifndef __GROUP_H
>> >#define __GROUP_H
>> >
>> >
>> >#include <string>
>> >
>> >
>> >namespace kaimei{
>> >...
>> }
>> >
>> >
>> >namespace cppcms {
>> >  namespace json {
>> >    template<>
>> >      struct traits<kaimei::group> {
>> >...
>> >      }
>> >  }
>> >}
>> >
>> >
>> >
>> > [snip]
>> >
>> >I am not good at template programming. Why did this happen?
>> >
>>
>> You can't specialize undefined struct - you need to include
>> <cppcms/json.h>
>> header. It provides the original traits struct and than you specialize it
>> for
>> your type of class
>>
>>
>> >
>> >陈抒
>> >Best regards
>> >http://blog.csdn.net/sheismylife
>> >
>>
>> Regards,
>> Artyom
>>
>>
>>
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>>
>
>