Qt boost serialize compile errors on simple implementation - boost

Platform specifics:
Fedora 21
g++ 4.9.2-6
Here's the error ....
$ g++ -c kabi-serial.cpp -lboost_serialization
kabi-serial.cpp: In function ‘void boost::serialization::kb_write_list()’:
kabi-serial.cpp:41:13: error: expected ‘;’ before ‘oa’
serialize oa(ofs);
kabi-serial.cpp:41:20: error: statement cannot resolve address of overloaded function
serialize oa(ofs);
^
kabi-serial.cpp:42:3: error: ‘oa’ was not declared in this scope
oa << ql;
And here's the kabi-serial.cpp source ...
#include <boost/serialization/vector.hpp>
#include <vector>
namespace boost {
namespace serialization {
class Cqnodelist
{
public:
friend class boost::serialization::access;
Cqnodelist(){}
std::vector<int>qnodelist;
template<class Archive>
void serialize(Archive & ar, const unsigned int version)
{
ar & qnodelist;
}
};
void kb_write_list ()
{
Cqnodelist ql;
ofstream ofs("kabi-list.dat");
{
serialize oa(ofs);
oa << ql;
}
}
}
}
I based the source code on the simplest of the serialization examples, except using the serialization of the stl vector object.
I'm sure it's simple, but what am I missing?

To use ofstream you need to include <fstream>.
ofstream is in the namespace std: std::ofstream.
You don't need to put your code inside boost::serialization namespace (except case when you implement external to class serialize() function).
Adding serialize method implements way of loading and saving object attributes.
To actually store or load data you need to select storage — archive in Boost.Serialization terminology.
#include <boost/serialization/vector.hpp>
// include headers that implement a archive in simple text format
#include <boost/archive/text_oarchive.hpp>
#include <boost/archive/text_iarchive.hpp>
#include <vector>
#include <fstream> // required for std::ofstream
class Cqnodelist
{
public:
friend class boost::serialization::access;
Cqnodelist(){}
std::vector<int>qnodelist;
template<class Archive>
void serialize(Archive & ar, const unsigned int version)
{
ar & qnodelist;
}
};
void kb_write_list ()
{
Cqnodelist ql;
// fill object with data
ql.qnodelist.push_back(1);
ql.qnodelist.push_back(2);
ql.qnodelist.push_back(3);
// See http://www.boost.org/doc/libs/1_57_0/libs/serialization/doc/tutorial.html
// for reference
// save data to archive
{
// open file that will contain serialized data
std::ofstream ofs("kabi-list.dat");
// create archive on top of opened file
boost::archive::text_oarchive oa(ofs);
// write class instance to archive
oa << ql;
}
// to load object later open file, create input archive on top of opened
// file and load object state
{
Cqnodelist new_ql;
// create and open an archive for input
std::ifstream ifs("kabi-list.dat");
boost::archive::text_iarchive ia(ifs);
// read class state from archive
ia >> new_ql;
}
}
int main()
{
kb_write_list();
}

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having difficulties to make a vector of polymorphic objects using shared_ptr and unique_ptr in C++ Visual studio 2019 Cmake project

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*note:
we use Cmake to bind the project together in visual studio
and also we splitting the objects into header and cpp files.
here are my objects for now:
//This is the abstract base class
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#include <string>
class Shape
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public:
Shape() = default;
virtual ~Shape() = default;
virtual std::string get_name() = 0;
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};
These are the derived classes:
#pragma once
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std::string m_name;
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Cpp file:
#pragma once
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}
Circle::~Circle()
{
}
std::string Circle::get_name() override
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another derived class:
#pragma once
#include "Shape.h"
class Rectangle : public Shape
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public:
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~Rectangle();
virtual std::string get_name() override;
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Cpp file:
#pragma once
#include "Rectangle.h"
Rectangle::Rectangle()
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Rectangle::~Rectangle()
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}
std::string Rectangle::get_name() override
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return m_name;
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this is the class that operates the program:
#pragma once
#include <iostream>
#include <string>
#include <vector>
#include <memory>
#include "Shape.h"
#include "Circle.h"
#include "Rectangle.h"
class Board
{
public:
Board();
~Board();
void run();
void objects_allocation();
private:
std::string m_string;
std::vector<std::shared_ptr<Shape>> m_gates;
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Cpp file:
#pragma once
#include "Board.h"
Board::Board()
: m_string(" ")
{
}
Board::~Board()
{
}
void run()
{
while (m_string != "exit")
{
std::cin >> m_string;
}
std::cout << "Goodbye!" << std::endl;
}
void Board::Objects_allocation()
{
m_gates.push_back(std::make_shared <Circle>());
m_gates.push_back(std::make_shared <Rectangle>());
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and here is my main function:
#pragma once
#include "Board.h"
int main()
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Board board1;
board1.run();
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sincerely thank you if you could explain to me what went wrong here..
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wxWidgets event table with custom event

I'm trying to implement a custom event in my wxWidgets application but I can't write the event table macros in a proper way.
the files that I use to implement the event is like the following:
the .h file
#ifndef __APP_FRAME_H__
#define __APP_FRAME_H__
#include "wx/wxprec.h"
#ifndef WX_PRECOMP
#include "wx/wx.h"
#endif
#include <wx/evtloop.h>
#include "wxApp.h"
#include "sampleCefApp.h"
class appFrame: public wxFrame
{
public:
appFrame(const wxString &title, const wxPoint &pos, const wxSize &size);
private:
int OnExit();
void OnCefStartEvent(wxCommandEvent &e);
DECLARE_EVENT_TABLE()
};
#endif
the .cpp file
// File : appFrame.cpp
#include "appFrame.h"
wxDEFINE_EVENT(CEF_START_EVT, wxCommandEvent)
void appFrame::OnCefStartEvent(wxCommandEvent &e)
{
CefRunMessageLoop();
}
int appFrame::OnExit(){
CefShutdown();
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}
appFrame::appFrame(const wxString &title, const wxPoint &pos, const wxSize &size)
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{
}
wxBEGIN_EVENT_TABLE(appFrame, wxFrame)
EVT_COMMAND(wxID_ANY, CEF_START_EVT, appFrame::OnCefStartEvent)
wxEND_EVENT_TABLE()
And when I build my make file I get the following errors:
../src/appFrame.cpp:4:15: error: expected constructor, destructor, or type conversion before ‘(’ token
../src/appFrame.cpp:24:2: error: expected constructor, destructor, or type conversion before ‘wxEventTableEntry
I think the problem is related to mis-placing event table macros.
I want to know what is the problem exactly and how to fix it ?
You need a semicolon after wxDEFINE_EVENT() macro (as for almost all macros with wx prefix, they consistently require a semicolon, unlike the legacy macros without the prefix).
As usual, see the sample for the example of use of this macro.

How to write a C++ API class that will allow a user to register its own callback functions?

Let's say a user links his app against a library I wrote and I want to let him specify a callback function that I will call whenever an error occurs in my library. The implementation below works but I want to double check that I'm not missing something here:
Thread safety
DLL initialization issues
Public API considerations (I'm giving away a reference to an instance from the DLL is that OK?)
Anything that could be done better to hide implementation details from the public API?
errordispatcher.h:
#pragma once
#include <functional>
#include <memory>
#include <string>
namespace WE
{
class ErrorDispatcher
{
public:
ErrorDispatcher()
{}
explicit ErrorDispatcher(std::function<void(std::string)> user_func)
: error_callback_func{user_func}
{}
virtual ~ErrorDispatcher(){}
static ErrorDispatcher& getInstance()
{
return instance_;
}
void setErrorCallback(std::function<void(std::string)> user_func)
{
error_callback_func = nullptr;
if (user_func)
error_callback_func = user_func;
}
void dispatchError(std::string message)
{
if (error_callback_func)
error_callback_func(message);
}
private:
explicit ErrorDispatcher(const ErrorDispatcher&) = delete;
explicit ErrorDispatcher(ErrorDispatcher&&) = delete;
ErrorDispatcher& operator = (const ErrorDispatcher&) = delete;
ErrorDispatcher& operator = (ErrorDispatcher&&) = delete;
static ErrorDispatcher instance_;
std::function<void(std::string)> error_callback_func = nullptr;
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NOTE: above I have inline implementation details in the public header to make this post shorter but they will be moved to a .cpp and won't be part of the public header
errordispatcher.cpp:
#include "errordispatcher.h"
namespace WE
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ErrorDispatcher ErrorDispatcher::instance_;
}
apitest.h
namespace WE
{
void dllFunctionThatMightGiveError();
}
apitest.cpp
#include "errordispatcher.h"
#include "apitest.h"
namespace WE
{
void dllFunctionThatMightGiveError()
{
// Some error happens in dll so call user function and give a message to the user!
ErrorDispatcher::getInstance().dispatchError("Error in DLL!");
}
}
main.cpp (USER APP)
#include "errordispatcher.h"
#include "apitest.h"
#include <iostream>
#include <string>
void error_callback(std::string message)
{
std::cout << message << "\n";
}
int main(void)
{
WE::ErrorDispatcher::getInstance().setErrorCallback(error_callback);
WE::ErrorDispatcher::getInstance().dispatchError("Error in APP!");
WE::dllFunctionThatMightGiveError();
return 0;
}
Output is:
Error in APP!
Error in DLL!

Google mock does not compile with boost::variant of std::vector

I am trying to create Google Mock object for some interface class which uses boost::variant
#include <gtest/gtest.h>
#include <gmock/gmock.h>
#include <boost/variant.hpp>
#include <vector>
typedef std::vector<int> VectorOfInt;
typedef boost::variant<VectorOfInt> VariantOfVector;
class InterfaceClass
{
public:
virtual ~InterfaceClass() {}
virtual void SetSome( const VariantOfVector& ) = 0;
virtual const VariantOfVector& GetSome() const = 0;
};
class MockInterfaceClass
{
public:
MOCK_METHOD1( SetSome, void( const VariantOfVector& ) );
MOCK_CONST_METHOD0( GetSome, const VariantOfVector&() );
};
When I compile it with
g++ mytest.cpp -o mytest
i get
/usr/include/boost/variant/detail/variant_io.hpp:64: error: no match for ‘operator<<’ in ‘((const boost::detail::variant::printer > >*)this)->boost::detail::variant::printer > >::out_ << operand’
Does boost::variant work with std::vector? It seems boost::variant works with any type I define but std:vector. Why?
Boost version - 1.45
g++ version - 4.4.5
It seems that the mock attempts to apply operator << to your variant. You have to define operator << for its contents, i.e. for std::vector template.
As Igor R. answered, you need to add operator << (without namespace) like this:
std::ostream& operator <<(std::ostream& out, VariantOfVector const& rhs)
{
//Print or apply your visitor to **rhs**
return out;
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Boost serialization polymorphic register(export) not working across files

I am using boost::serialization in my project. The project is large, and serializes my objects in several places. According to the documentation here, I should export my class with two separated step.
BOOST_EXPORT_KEY() in .h file, witch contains the declaration.
BOOST_EXPOET_IMPLEMENT() in .cpp file, witch contains the instantiation(definition) of the exporting.
hier.h the class hierarchy, there are 3 classes in the hierarchy.
/*
B <---+--- D1
|
+--- D2
*/
#include <boost/serialization/base_object.hpp>
class B {
public:
virtual ~B() {}
template < typename Ar >
void serialize(Ar& ar, const int) {
}
} ;
class D1 : public B {
public:
virtual ~D1() {}
template < typename Ar > void serialize(Ar& ar, const int) {
boost::serialization::base_object<B>(*this);
}
} ;
class D2 : public B {
public:
template < typename Ar > void serialize(Ar& ar, const int) {
boost::serialization::base_object<B>(*this);
}
virtual ~D2() {}
} ;
#include <boost/serialization/export.hpp>
BOOST_CLASS_EXPORT_KEY(B);
BOOST_CLASS_EXPORT_KEY(D1);
BOOST_CLASS_EXPORT_KEY(D2);
And a hier.cpp contains the implementation:
#include <boost/serialization/export.hpp>
#include "hier.h"
BOOST_CLASS_EXPORT_IMPLEMENT(D1);
BOOST_CLASS_EXPORT_IMPLEMENT(D2);
And a main.cpp use the serialization:
#include <iostream>
#include <sstream>
#include <boost/archive/text_iarchive.hpp>
#include <boost/archive/text_oarchive.hpp>
#include <boost/serialization/export.hpp>
#include "hier.h"
int main(int argc, char* argv[])
{
B* d1 = new D1();
B* d2 = new D2();
std::ostringstream os;
boost::archive::text_oarchive oa (os);
oa & d1 & d2;
}
It compiled without any problem, but run it will cause:
terminate called after throwing an instance of 'boost::archive::archive_exception'
what(): unregistered class - derived class not registered or exported
Which means the derived class is not registered, means the registration in the hier.cpp is not working. But that is really strange, because:
If I register implementation is both main.cpp and hier.cpp, it issue duplicated definition while linking. Means the registration in hier.cpp is OK and is exposed into the linkers visibility., otherwise there will be no duplicated definition error.
If I register implementation only in main.cpp, it runs OK.
I am really confused in that situation. Any comment and suggestion is appreciated. Thanks in advance.
Before calling BOOST_CLASS_EXPORT_* you should include the archives which you want to use. The maсro then adds specific serialize-functions for the headers.
This means you should change your code in hier.cpp to the following:
#include <boost/serialization/export.hpp>
#include <boost/archive/text_iarchive.hpp>
#include <boost/archive/text_oarchive.hpp>
#include "hier.h"
BOOST_CLASS_EXPORT_IMPLEMENT(D1);
BOOST_CLASS_EXPORT_IMPLEMENT(D2);
The code in hier.h changes accordingly:
#include <boost/serialization/export.hpp>
#include <boost/archive/text_iarchive.hpp>
#include <boost/archive/text_oarchive.hpp>
BOOST_CLASS_EXPORT_KEY(B);
BOOST_CLASS_EXPORT_KEY(D1);
BOOST_CLASS_EXPORT_KEY(D2);
Sources:
Boost Serialization Documentation
PS:
I do not know if this is solving your problem, but I think it could be causing some trouble. I think it's worth a try.

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