sizeof class inside a member function of that class - visual-c++

#include "stdafx.h"
#include<iostream>
using namespace std;
class Myclass
{
public:
void Displaysize()
{
cout<<sizeof(Myclass);
}
private:
int x, y, z;
};
int _tmain(int argc, _TCHAR* argv[])
{
Myclass Ob;
Ob.Displaysize();
return 0;
}
When I execute this I got the size of class as 12, which is correct, how compiler come to now the size of the class properly. I read in Geeks for Geeks as follows "If a non-static object is member then declaration of class is incomplete and compiler has no way to find out size of the objects of the class."
Could some one answer my query.

Related

When i am creating object ,compiler gives error C4430

I am getting these two errors
Error # 01:
error C2146: syntax error : missing ';' before identifier 'mainObj'
Error # 02
error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
i have following classes
Main
Customer
CNode
when i create pointer object of class 'CNode' in class 'Customer' ,there is no error. But when i create non pointer object of Main class in Customer class
,compiler gives above two errors.
while 'Main' class have a main fuction.
please help me out to resolve these errors.
Main.h
#pragma once
#include <iostream>
#include<string>
#include<conio.h>
#include<fstream>
#include<iomanip>
#include <sstream>
#include "Customer.h"
using namespace std;
class Main
{
int acc;
int total = 0;
int rtotal = 0;
int sum = 0;
public:
Main();
void design();
void welcome();
string passcin();
void login_des();
void admin_account();
void add_staff();
void delete_staff(int);
void search_staff(int);
void update_staff(int);
void room_display();
void room_book();
void checkout();
int main();
};
Customer.h
#pragma once
#include <iostream>
#include<string>
#include<fstream>
#include <sstream>
#include "Main.h"
#include "Node.h"
class Customer
{
CNode *head, *tail, * temp;
Main mainObj;
public:
Customer();
bool search(string, string);
void updateAccount(string, string);
CNode* inputNode();
void custAccount(string);
void createAccount();
void createAccount(CNode *);
void addCust();
void deleteCust(int sno);
void searchCust(int sno);
void updateCust(int sno);
void displayCust();
CNode* retriveAllCust();
};
Node.h
#pragma once
#include <iostream>
#include<string>
#include<fstream>
using namespace std;
class CNode
{
string name, email, pass, roomNo, phoneNo, country, creditCardName, cardNo;
bool bookFlag;
CNode *prev, *next;
int length;
public:
CNode();
CNode(string n, string e, string ps, string r, string pn, string country, string creditName, string creditNo, bool bookFlag);
CNode(string n, string e, string ps, string pn, string country);
string getName();
string getPass();
CNode* getNextNode();
void display();
void addCust();
string retriveCust();
friend class Customer;
};
I have put a semi colon before mainObj
like
;Main mainObj;
error occors in Customer Class
in
Main mainObj;

How to export a __interface derived class in visual c++?

I want to export a class type that derives from a __interface(only available for Visual c++),which aiming to create c#-like inteface-oriented experience.
//This wiil be defined in a "Famous.h"
__interface IFoo {
int GetNum();
};
//And this is my implementation.
#include "...Famous.h"
class FooImpl : public IFoo
{
public:
FooImpl(int a);
private:
int a;
};
FooImpl::FooImpl(int a)
{
this->a = a;
}
The problem is ,How could I export the 'FoolImpl' type to use it as follows in another project without refrencing the project directly.I tried dllexport,and tons of errors make me exthausted :(.
#include "..Impl.h"
#include "..Famous.h"
void main(){
IFoo* foo = new FooImpl(2);
...
}
Considering of there's no interface in c++,I replaced the __interface with pure virtual class.
//This wiil be defined in a "Famous.h"
#ifdef FAMOUS_EXPORTS
#define XYZAPI __declspec(dllexport)
#else
#define XYZAPI __declspec(dllimport)
#endif
class XYZAPI IFoo {
virual int GetNum() = 0;//void type also valid.
};
//And this is my implementation(Impl.h).
#ifdef IMPL_EXPORTS
#define XYZAPI __declspec(dllexport)
#else
#define XYZAPI __declspec(dllimport)
#endif
#include "...Famous.h"
class XYZAPI FooImpl : public IFoo
{
public:
FooImpl(int a);
private:
int a;
};
FooImpl::FooImpl(int a)
{
this->a = a;
}
And this is my invocation.
#include "..Impl.h"
#include "..Famous.h"
void main(){
IFoo* foo = new FooImpl(2);
...
}

C++ Windows Form Application: Attempted to read or write protected memory (unmanaged class)

I'm trying to use Boost library in my C++ Windows Form Application and I always get an exception:
Additional information: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.
I'm using Visual Studio 2012 and Boost version 1.57.0. Previously I used Boost version 1.56.0 but upgrading didn't solve my issue.
Here are the code:
MyForm.cpp
#include "MyForm.h"
using namespace System;
using namespace System::Windows::Forms;
[STAThread]
void main(cli::array<String^>^ args) {
Application::EnableVisualStyles();
Application::SetCompatibleTextRenderingDefault(false);
TestUnmanaged::MyForm form;
Application::Run(%form);
}
MyForm.h
#pragma once
#include <iostream>
#include <map>
#include <sstream>
#include <cassert>
#include <stdio.h>
#include "ExternalProfileManager.h"
#define DEFAULT_PROFILE_NAME "profile.bin"
#pragma comment(lib, "Ws2_32.lib")
#pragma comment(lib, "lib/edk.lib")
namespace TestUnmanaged {
using namespace System;
using namespace System::ComponentModel;
using namespace System::Collections;
using namespace System::Windows::Forms;
using namespace System::Data;
using namespace System::Drawing;
ExternalProfileManager profileManager;
/// <summary>
/// Summary for MyForm
/// </summary>
public ref class MyForm : public System::Windows::Forms::Form
{
public:
MyForm(void)
{
InitializeComponent();
//
//TODO: Add the constructor code here
//
profileManager.load(DEFAULT_PROFILE_NAME);
std::vector<std::string> profileList;
profileManager.listProfile(profileList);
}
ExternalProfileManager.h
#ifndef EXTERNAL_PROFILE_MANAGER_H
#define EXTERNAL_PROFILE_MANAGER_H
#include <boost/serialization/string.hpp>
#include <boost/serialization/map.hpp>
#include <boost/serialization/vector.hpp>
#include <boost/serialization/export.hpp>
#include <boost/serialization/tracking.hpp>
#include <boost/serialization/base_object.hpp>
class ExternalProfileManager
{
ExternalProfileManager(const ExternalProfileManager&) {};
ExternalProfileManager& operator = (const ExternalProfileManager&) {};
protected:
std::map<std::string, std::string > _profiles;
typedef std::map<std::string, std::string >::iterator profileItr_t;
// Boost serialization support
friend class boost::serialization::access;
template <class Archive>
void serialize(Archive& ar, const unsigned int /*file version */)
{
ar & _profiles;
}
public:
ExternalProfileManager();
virtual ~ExternalProfileManager();
virtual bool save(const std::string& location);
virtual bool load(const std::string& location);
virtual bool insertProfile(const std::string& name, const unsigned char* profileBuf, unsigned int bufSize);
virtual bool listProfile(std::vector<std::string>& profiles);
};
//BOOST_CLASS_EXPORT(ExternalProfileManager);
//BOOST_CLASS_TRACKING(ExternalProfileManager, boost::serialization::track_never);
#endif // EXTERNAL_PROFILE_MANAGER_H
ExternalProfileManager.cpp
#include <fstream>
#include <boost/filesystem/operations.hpp>
#include <boost/filesystem/path.hpp>
#include <boost/regex.hpp>
#pragma warning(push)
#pragma warning(disable : 4267) // "conversion from size_t to unsigned int"
#pragma warning(disable : 4996)
#include <boost/archive/archive_exception.hpp>
#include <boost/archive/binary_oarchive.hpp>
#include <boost/archive/binary_iarchive.hpp>
#pragma warning(pop)
#include "ExternalProfileManager.h"
using namespace std;
namespace fs = boost::filesystem;
ExternalProfileManager::ExternalProfileManager()
{
}
ExternalProfileManager::~ExternalProfileManager()
{
}
bool ExternalProfileManager::save(const string& location)
{
ofstream ofs(location.c_str(), ios_base::binary);
if ( !ofs.is_open() ) return false;
try {
boost::archive::binary_oarchive oa(ofs);
oa << *this;
}
catch (boost::archive::archive_exception& )
{
return false;
}
return true;
}
bool ExternalProfileManager::load(const string& location)
{
ifstream ifs(location.c_str(), ios_base::binary);
if ( !ifs.is_open() ) return false;
try {
boost::archive::binary_iarchive ia(ifs);
ia >> *this;
}
catch (boost::archive::archive_exception& )
{
return false;
}
return true;
}
bool ExternalProfileManager::insertProfile(const string& name, const unsigned char* profileBuf, unsigned int bufSize)
{
assert(profileBuf);
// Replace our stored bytes with the contents of the buffer passed by the caller
string bytesIn(profileBuf, profileBuf+bufSize);
_profiles[name] = bytesIn;
return true;
}
bool ExternalProfileManager::listProfile(vector<string>& profiles)
{
profiles.clear();
for ( profileItr_t itr = _profiles.begin(); itr != _profiles.end(); ++itr ) {
profiles.push_back(itr->first);
}
return true;
}
The error occurred in ia >> *this; in ExternalProfileManager::load (thrown in file basic_archive.cpp). So calling profileManager.load(DEFAULT_PROFILE_NAME); from form constructor will trigger the exception.
Calling save will also trigger the same exception but other functions which have no this will work fine.
I tried creating a console application in VS 2012 and call ExternalProfileManager.h and it works perfectly (including save, load, and any other function). Here are the simple console application I created to test it:
Console.cpp
#include <iostream>
#include <map>
#include <sstream>
#include <cassert>
#include <stdio.h>
#include "ExternalProfileManager.h"
#define DEFAULT_PROFILE_NAME "profile.bin"
#pragma comment(lib, "Ws2_32.lib")
#pragma comment(lib, "lib/edk.lib")
ExternalProfileManager profileManager;
int main(int argc, char** argv) {
profileManager.load(DEFAULT_PROFILE_NAME);
std::vector<std::string> profileList;
profileManager.listProfile(profileList);
std::cout << "Available profiles:" << std::endl;
for (size_t i=0; i < profileList.size(); i++) {
std::cout << i+1 << ". " << profileList.at(i);
if (i+1 < profileList.size()) {
std::cout << std::endl;
}
}
return true;
}
profile.bin is generated from calling save function in console application and contain serialized data generated by boost. I can provide the file if it is needed to solve this issue.
I have also tried to create a simple class wrapper but the exception still occurred.
WrapperExternalProfileManager.h
#ifndef WRAPPER_EXTERNAL_PROFILE_MANAGER_H
#define WRAPPER_EXTERNAL_PROFILE_MANAGER_H
#include <string>
#include <vector>
class WrapperExternalProfileManager
{
WrapperExternalProfileManager(const WrapperExternalProfileManager&) {};
WrapperExternalProfileManager& operator = (const WrapperExternalProfileManager&) {};
public:
WrapperExternalProfileManager();
virtual ~WrapperExternalProfileManager();
virtual bool save(const std::string& location);
virtual bool load(const std::string& location);
virtual bool insertProfile(const std::string& name, const unsigned char* profileBuf, unsigned int bufSize);
virtual bool listProfile(std::vector<std::string>& profiles);
};
#endif
WrapperExternalProfileManager.cpp
#include "WrapperExternalProfileManager.h"
#include "ExternalProfileManager.h"
using namespace std;
ExternalProfileManager profileManager;
WrapperExternalProfileManager::WrapperExternalProfileManager()
{
std::cout<<"Constructor WrapperExternalProfileManager"<<std::endl;
}
WrapperExternalProfileManager::~WrapperExternalProfileManager()
{
}
bool WrapperExternalProfileManager::save(const string& location)
{
return profileManager.save(location);
}
bool WrapperExternalProfileManager::load(const string& location)
{
return profileManager.load(location);
}
bool WrapperExternalProfileManager::insertProfile(const string& name, const unsigned char* profileBuf, unsigned int bufSize)
{
return profileManager.insertProfile(name, profileBuf, bufSize);
}
bool WrapperExternalProfileManager::listProfile(vector<string>& profiles)
{
return profileManager.listProfile(profiles);
}
save and load still trigger the exception but other functions work perfectly.
Here are some property of the application which might be helpful:
Linker -> System -> SubSystem: Windows (/SUBSYSTEM:WINDOWS)
General -> Common Language Runtime Support: Common Language Runtime Support (/clr)
I know I have done something incorrectly but I don't know which part. Any suggestion to solve this issue would be appreciated.
Thanks in advance
You're going to have to find the source of your Undefined Behaviour (use static analysis tools, heap checking and divide and conquer).
I've just built your code on VS2013 RTM, using a ultra-simple C# console application as the driver:
namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
var f = new TestUnmanaged.MyForm();
f.ShowDialog();
}
}
}
This JustWorks(TM).
I created a profile.bin with 100 random profiles of varying length:
#if 1
for (int i = 0; i < 100; ++i)
{
std::vector<uint8_t> buf;
std::generate_n(back_inserter(buf), rand() % 1024, rand);
insertProfile("profile" + std::to_string(i), buf.data(), buf.size());
}
save(location);
#endif
And they are deserialized just fine.
Good luck.
Download the full project here http://downloads.sehe.nl/stackoverflow/q27032092.zip in case you want to fiddle with it (compare the details?)

Visual C++ Errors C2146, C4430

Please help to figure out whats wrong with this code.
main.cpp create Object3D which create Box and pass Object3D* pointer to Box.
And there are errors until i remove Object3D declarations from Box.
main.cpp
#include <iostream>
#include "stdafx.h"
#include "Object3D.h"
int _tmain(int argc, _TCHAR* argv[])
{
Object3D obj;
char c;
std::cin >> c;
return 0;
}
Object3D.cpp
#include "Object3D.h"
#include "Box.h"
Object3D::Object3D()
{}
Object3D::~Object3D()
{}
Object3D.h
#ifndef OBJECT3D_H
#define OBJECT3D_H
#include "Box.h"
class Object3D
{
public:
Object3D();
~Object3D();
private:
Box _box_obj; //<<<---ERROR HERE (C2146, C4430)
};
#endif
Box.cpp
#include "Box.h"
#include "Object3D.h"
int Box::Init(Object3D* _obj)
{
obj = _obj;
}
Box::Box()
{}
Box::~Box()
{}
Box.h
#ifndef BOX_H
#define BOX_H
#include "Object3D.h"
class Box
{
public:
Object3D* obj; //<<<---ERROR HERE (C2143, C4430)
int Init(Object3D* _obj); //<<<---ERROR HERE (C2061)
Box();
~Box();
};
#endif
Change Box.h:
#ifndef BOX_H
#define BOX_H
// forward reference possible since the class is not dereferenced here.
class Object3D;
class Box
{
public:
Object3D* obj;
int Init(Object3D* _obj);
Box();
~Box();
};
#endif
The class definition does not use any member of Object3D. Therefore you don't need to know the definition of Object3D but just the fact that it is a class. The forward reference is sufficient and an appropriate tool to resolve a circular dependency.
BTW: The circular reference of object usually includes some "master" objects that own the other objects. It makes sense to change the member name to show the relation rather the type. I would suggest a
Object3D* owner;
when the box owns the obj.

Cuda - printing string from object in __global__ function

I am new to CUDA and I am getting a strange error. I want to print a string from a passed object and I get the error "calling host function from global function is not allowed" and I don't know why. But if I want to print an integer (changing get method to return sk1), everything works fine. Here is the code:
class Duomenys {
private:
string simb;
int sk1;
double sk2;
public:
__device__ __host__ Duomenys(void): simb(""), sk1(0), sk2(0.0) {}
__device__ __host__~Duomenys() {}
__device__ __host__ Duomenys::Duomenys(string simb1, int sk11, double sk21)
: simb(simb1), sk1(sk11), sk2(sk21) {}
__device__ __host__ string Duomenys::get(){
return simb;
}
};
And here I am calling Duomenys::get from __global__ function:
__global__ void Vec_add(Duomenys a) {
printf(" %s \n",a.get());
}
EDIT: I am trying to read data from a file and print it in a global function. In this code I am trying read all data and print just one object to see if everything works. This is the error I'm getting:
calling a __host__ function("std::basic_string<char, std::char_traits<char>, std::allocator<char> >::~basic_string") from a __global__ function("Vec_add") is not allowed
Code:
#include <stdio.h>
#include <stdlib.h>
#include <cuda.h>
#include <cuda_runtime.h>
#include <vector>
#include <string>
#include <iostream>
#include <fstream>
#include <iomanip>
#include <string>
#include <sstream>
using namespace std;
class Duomenys {
private:
string simb;
int sk1;
double sk2;
public:
__device__ __host__ Duomenys(void): simb(""), sk1(0), sk2(0.0) {}
__device__ __host__~Duomenys() {}
__device__ __host__ Duomenys::Duomenys(string simb1, int sk11, double sk21)
: simb(simb1), sk1(sk11), sk2(sk21) {}
__device__ __host__ string Duomenys::print()
{
stringstream ss;
ss << left << setw(10) << simb << setw(10) << sk1 << setw(10) << sk2;
return ss.str();
}
};
__global__ void Vec_add(Duomenys a) {
printf(" %s \n",a.print());
}
/* Host code */
int main(int argc, char* argv[]) {
setlocale (LC_ALL,"");
vector<Duomenys> vienas;
vector<vector<Duomenys>> visi;
//data reading to vector "vienas" (it works without any errors)
Duomenys *darr;
const size_t sz = size_t(2) * sizeof(Duomenys);
cudaMalloc((void**)&darr, sz);
Vec_add<<<1, 1>>>(visi[0].at(0));
cudaDeviceSynchronize();
cudaMemcpy(darr, &visi[0].at(0), sz, cudaMemcpyHostToDevice);
return 0;
}
Your problem is not with printf function, but with string data type. You cannot use the C++ string type in a kernel. See related question here: Can we use the string data type in C++ within kernels
Why would you pass a string object to printf when the %s format specifier is expecting something else? When I try to do that in ordinary host code, I get warnings about "passing non-POD types through ellipsis (call will abort at runtime)". Note that this problem has nothing to do with CUDA.
But beyond that issue, presumably you're getting string from the C++ standard library. (It's better if you show a complete reproducer code, then I don't have to guess at where you're getting things or what you are including.)
If I get string as follows:
#include <string>
using namespace std;
Then I am using a function defined in the C++ Standard Library. CUDA supports the C++ language (mostly) but does not necessarily support usage of C++ libraries (or C libraries, for that matter) in device code. Libraries are (usually) composed of (at least some) compiled code (such as allocators, in this case), and this code has been compiled for CPUs, not for the GPU. When you try to use such a CPU compiled routine (e.g. an allocator associated with the string class) in device code, the compiler will bark at you. If you include the complete error message in the question, it will be more obvious specifically what (compiled-for-the-host) function is actually the issue.
Use a standard C style string instead (i.e. char[] and you will be able to use it directly in printf.
EDIT: In response to a question in the comments, here is a modified version of the code posted that demonstrates how to use an ordinary C-style string (i.e. char[]) and print from it in device code.
#include <stdio.h>
#include <stdlib.h>
#include <cuda.h>
#include <cuda_runtime.h>
#include <vector>
#include <iostream>
#include <fstream>
#include <iomanip>
#include <string>
#include <sstream>
#define STRSZ 32
using namespace std;
class Duomenys {
private:
char simb[STRSZ];
int sk1;
double sk2;
public:
__device__ __host__ Duomenys(void): sk1(0), sk2(0.0) {}
__device__ __host__~Duomenys() {}
__device__ __host__ Duomenys(char *simb1, int sk11, double sk21)
: sk1(sk11), sk2(sk21) {}
__device__ __host__ char * print()
{
return simb;
}
__device__ __host__ void store_str(const char *str)
{
for (int i=0; i< STRSZ; i++)
simb[i] = str[i];
}
};
__global__ void Vec_add(Duomenys a) {
printf(" %s \n",a.print());
}
/* Host code */
int main(int argc, char* argv[]) {
string host_string("hello\n");
setlocale (LC_ALL,"");
vector<Duomenys> vienas(3);
vienas[0].store_str(host_string.c_str());
vector<vector<Duomenys> > visi(3);
visi[0] = vienas;
//data reading to vector "vienas" (it works without any errors)
Duomenys *darr;
const size_t sz = size_t(2) * sizeof(Duomenys);
cudaMalloc((void**)&darr, sz);
Vec_add<<<1, 1>>>(visi[0].at(0));
cudaDeviceSynchronize();
cudaMemcpy(darr, &(visi[0].at(0)), sz, cudaMemcpyHostToDevice);
return 0;
}
Note that I didn't try to understand your code or fix everything that looked strange to me. However this should demonstrate one possible approach.

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