Re: [Boost-users] Serialization: Visual C+ Template Bug ?

30 Nov 2007

      Sry but I do not understand. I do specify the implementation with

template<class Archive>
        void PaloClient::serialize( Archive &ar, const unsigned int version
) {
            ar & m_PaloClientImpl;
        }

as you suggest and as I have written in example 1.
Then I write

template void PaloClient::serializeboost::archive::text_iarchive(
            boost::archive::text_iarchive & ar,
            const unsigned int file_version
            );

        template void PaloClient::serializeboost::archive::text_oarchive(
            boost::archive::text_oarchive & ar,
            const unsigned int file_version
            );

to make the compiler generate code for these two template parameters.
It works for me in other cases and it is what the documentation says.
I dont think that removing the two template-specification could solve the
issue,
since the template function-definition is not included in any header file.
There must be some misunderstanding.

Kind regards, Oliver

On Nov 29, 2007 5:27 PM, Robert Ramey  wrote:
...
This is a C++ syntax issue.
The first example explicitly instantiates the serialize declaration
without specifying its implementation
which leads to an undefined symbol. just use:
template<class Archive>
        void PaloClient::serialize( Archive &ar, const unsigned int
version ) {
            ar & m_PaloClientImpl;
        }
and the appropriate code wil be instantiated if and only if it is actually
invoked.
Robert Ramey
"Oliver Kania"  wrote in message
news:1262c4ee0711290739x12408875u39e54bbe9effb093@mail.gmail.com...
Hello !
When linking a program that consists only of main.cpp with a library that
serializes
a class "Palo Cllient"  I get the  following message (sry for the mess):
==================================================
 error LNK2019: unresolved external symbol "private: void __thiscall
jedox::palo::PaloClient::serialize<class
boost::archive::text_oarchive>(class boost::archive::text_oarchive
&,unsigned int)" (??$serialize@ Vtext_oarchive@archive@boost@@@
PaloClient@palo@jedox@@AAEXAAVtext_oarchive@archive@boost@@I@Z) referenced
in function "public: static void __cdecl
boost::serialization::access::serialize(class
boost::archive::text_oarchive &,class jedox::palo::PaloClient &,unsigned
int)" (??$serialize@ Vtext_oarchive@archive@boost@@VPaloClient@palo
@jedox@@@access@serialization@boost@@SAXAAVtext_oarchive@archive@
2@AAVPaloClient@palo@jedox@@I@Z)
==================================================
This happens even though I do NOT explicitly serialize anything.
Main.cpp includes:
#include 
#include 
For the class PaloClient, I do use the Pimpl idiom and serialize as it is
recommended
in the documentation:
PaloClient.cpp:
--------------------------------------------------------------
#include 
#include 
#include 
....
template<class Archive>
        void PaloClient::serialize( Archive &ar, const unsigned int
version ) {
            ar & m_PaloClientImpl;
        }
template void PaloClient::serializeboost::archive::text_iarchive(
            boost::archive::text_iarchive & ar,
            const unsigned int file_version
            );
template void
PaloClient::serializeboost::archive::text_oarchive(
            boost::archive::text_oarchive & ar,
            const unsigned int file_version
            );
------------------------------------------------------------------------
Now, when I change this to
void PaloClient::serialize(boost::archive::text_iarchive & ar,
const unsigned int file_version) {
            ar & m_PaloClientImpl;
        }
void PaloClient::serialize (boost::archive::text_oarchive & ar,
const unsigned int file_version) {
                ar & m_PaloClientImpl;
        }
The linkage error disappears. I guess this is a Visual C++ compiler
problem but
I wanted to post this in case someone else has similar problems.
Kind regards, Oliver
PS: Thanks for this great serialization library, it saved me many weeks of
programming.
------------------------------
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