I am writing a program in c++/cli and it is giving me the error:
Error C2872: 'String' : ambiguous symbol
I am using String as part of a function:
Dictionary<String^, List<array< Byte >^>^>^ FalseTrigg(Dictionary<String^, String^>^ imgParms, bool windowOn)
Below is the overall program. Thanks for any help.
#include <errno.h>
#include <vector>
#include <string>
#include <iostream>
#include <sstream>
#include <string>
#include <fstream>
#pragma managed(push, off)
#include "cv.h"
#include "highgui.h"
#include <stdio.h>
#include "opencv2/core/core.hpp"
#include "opencv2/features2d/features2d.hpp"
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/nonfree/nonfree.hpp"
#include <opencv2/nonfree/features2d.hpp>
#pragma managed(pop)
using namespace cv;
using namespace std;
using namespace System;
using namespace System::Collections::Generic;
using namespace System::Runtime::InteropServices;
public ref class FalseTrig
{
public:
FalseTrig() { }
~FalseTrig() { }
Dictionary<String^, List<array< Byte >^>^>^ FalseTrigg(Dictionary<String^, String^>^ imgParms, bool windowOn)
{}
};
You've got two definitions for the class String, and the compiler doesn't know which one you need. There should be more lines to the error message, which will list the various 'string' classes it found.
I'm not exactly sure which definitions it's finding, since std::string is supposed to be a lowercase "s", and you're using an uppercase "S".
In your method definition, just replace String^ with System::String^, and you should be good.
Alternatively, you could figure out which 'string' classes it's finding, and change your using namespace directives to not use the namespace that contains the other string class. You could also use a typedef to make String explicitly refer to System::String.
It looks like you have included the definition for String twice.
#include <errno.h>
#include <vector>
#include <string> //-> First time
#include <iostream>
#include <sstream>
#include <string> //-> Second time
#include <fstream>
Related
screenshot of my code and error data
This is my main.c file
#include "services_initialisations_prototype.h"
#include "services_functions_prototype.h"
void main(void)
{
initSfr();
while(1){
updateMatrix(404, 1);
}
return;
}
this is my services_initialisations_prototype.h
#ifndef XC_HEADER_TEMPLATE_H
#define XC_HEADER_TEMPLATE_H
#include <xc.h> // include processor files - each processor file is guarded.
#include <stdint.h>
//these are my function declarations
extern void initInterrupt();
extern void initIoc();
extern void initAdc();
extern void initTimer2();
extern void initSfr();
#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */
#ifdef __cplusplus
}
#endif /* __cplusplus */
#endif /* XC_HEADER_TEMPLATE_H */
this is my services_functions_prototype.h
#ifndef XC_HEADER_TEMPLATE_H
#define XC_HEADER_TEMPLATE_H
#include <xc.h> // include processor files - each processor file is guarded.
#include <stdint.h>
//these are my function declarations
extern void updateMatrix(int, int);
#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */
#ifdef __cplusplus
}
#endif /* __cplusplus */
#endif /* XC_HEADER_TEMPLATE_H */
When I try to include two header files in MPLAB X IDE version 4.05, it seems like it is not identifying the second header file. i tried swapping the order, but still the second one is not detected.
The services_initialisation_prototype.h contains initialisations of SFRs and services_functions_prototype.h contains prototypes of other functions. these functions are independent of each other.
when i compile, it is showing that
function updateMatrix() is declared as implicit int.
conflicting declarations for variable _updateMatrix()
which shows that the header file services_functions_prototype is not identified.
the screenshot attached shows the code in services_functions_prototype.h in grey color, and it seems that part of code is not executed.
When I copied the whole declarations from header file to my main file, it is working perfectly fine.
You used the same include guard in both files. Because one file is included before the other, it defines XC_HEADER_TEMPLATE_H which makes #ifndef fail in the second file. Change them to something unique. Wiki include guard.
Remember that identifiers with two leading underscores or identifiers with a leading underscore and an upper case letter are reserved by C standard. Good documentation online is in gcc reserved names.
Use filename with uppercase like SERVICES_FUNCTIONS_PROTOTYPE_H_ and SERVICES_INITIALIZATIONS_PROTOTYPE_H_.
Notes:
Empty parameter list in function declaration declares a function that takes unknown count and type of parameters. Prefer explicitly writing void inside function parameter list to define a function that takes no argument, to enable compiler static checking. Ie. do void initInterrupt(void);. cppreference function declaration
Identifiers declared at file scope are implicitly with external linkage. Ie. externis just redundant., just void initSfr(void); instead of extern void initSfr(); cppreference storage-class
The extern "C" { part makes no sense in your headers - there is nothing inside it. It's typicall to put extern "C" { on top of the header file to include everything inside. If your headers would be used by a C++ compiler, the functions names would be mangled and not properly resolved. I believe I would suggest to just remove the extern "C" { part.
Im trying to write a wrapper in c++/cli for an DLL, which code i dont have, only DLL file and header but i created lib file through VS command prompt. When i`m trying to build solution i receive this errors:
DotNetWrappOfAsterSdkDll.obj : error LNK2028: unresolved token (0A00002E) "void __stdcall MuteClearLastError(void)" (?MuteClearLastError##$$FYGXXZ) referenced in function "public: void __clrcall DotNetWrappOfAsterSdkDll::WrapperClass2::doMuteClearLastError(void)" (?doMuteClearLastError#WrapperClass2#DotNetWrappOfAsterSdkDll##$$FQ$AAMXXZ)
DotNetWrappOfAsterSdkDll.obj : error LNK2019: unresolved external symbol "void __stdcall MuteClearLastError(void)" (?MuteClearLastError##$$FYGXXZ) referenced in function "public: void __clrcall DotNetWrappOfAsterSdkDll::WrapperClass2::doMuteClearLastError(void)" (?doMuteClearLastError#WrapperClass2#DotNetWrappOfAsterSdkDll##$$FQ$AAMXXZ)
I tried to create my own DLL and include it to the wrapper, and its working perfectly
here dll created by me which i can use in c++/cli wrapper:
//header file
#pragma once
#define DLLEXP __declspec( dllexport )
namespace Computations {
DLLEXP void someMethod(int number);
}
//cpp file
#include "Computations.h"
#include <iostream>
#include <time.h>
//#include "pnl/pnl_random.h"
using namespace std;
void Computations::someMethod(int number)
{
std::cout << "something "<<number*number << endl;
}
and here is part of header of DLL which i want to use:
#ifndef MUTEIFC_H
#define MUTEIFC_H
#include <Windows.h>
#ifdef MUTEIFC_LIBRARY
# define MUTEAPI extern "C"__declspec(dllexport)
#else
# define MUTEAPI __declspec(dllimport)
#endif
#define MUTECALL __stdcall
/** \ingroup init */
/** Initialization of the ASTER SDK library
* \returns TRUE - success, FALSE - failure (use \ref MuteLastErrorCode or/and \ref MuteLastErrorInfo to get
* failure cause)
* \note This function will require Administrative privileges on the first call on a given computer.
*/
MUTEAPI BOOL MUTECALL MuteIfcInitialize(VOID);
/** \ingroup init */
/** Finialization of the ASTER SDK library
*/
MUTEAPI VOID MUTECALL MuteIfcFinalize(VOID);
/** \ingroup errors*/
/** Clears the calling thread's last-error code and description.
* The last-error is maintained on a per-thread basis. Multiple threads do not overwrite each other's last-error.
*/
MUTEAPI VOID MUTECALL MuteClearLastError(VOID);
#endif // MUTEIFC_H
and my c++/cli code :
//header file
#pragma once
#include "Computations.h"
#include "muteifc.h"
using namespace System;
namespace DotNetWrappOfAsterSdkDll
{
public ref class WrapperClass2
{
public:
void doMuteClearLastError();
};
public ref class WrapperClass
{
private:
public:
void getPriceCallEuro(int number);
};
}
//cpp file
#include "DotNetWrappOfAsterSdkDll.h"
using namespace DotNetWrappOfAsterSdkDll;
using namespace Computations;
namespace DotNetWrappOfAsterSdkDll
{
//this dont work
void WrapperClass2::doMuteClearLastError() {
MuteClearLastError();
}
//this works great
void WrapperClass::getPriceCallEuro(int number) {
someMethod(number);
//MuteIfcFinalize();
}
}
Please tell me what i'm doing wrong
You probably didn't add the lib that contains the function reference to the linker options.
Either the lib contains he code it self or it has a reference to the DLL that must be loaded. The linker will bring your code and the DLL (or static lib) code together...
I have been trying to do the following to no avail,
In 'used.h',
#ifndef USED_H_
#define USED_H_
#include<iostream>
#include<string>
class used
{
public:
int member=0;
used();
virtual ~used();
};
#endif
In the used.cc,
#include "used.h"
used::used()
{
}
used::~used()
{
}
In 'the_user.h',
#ifndef THE_USER_H_
#define THE_USER_H_
#include<queue>
#include<iostream>
class used; //Class forward declaring
class the_user
{
public:
std::deque<used*> my_queue;
the_user();
~the_user();
};
#endif
Now, I want to access and change 'member' in 'the_user.cc',
#include "used.h"
#include "the_used.h"
#include<iostream>
#include<queue>
using namespace std;
the_user::the_user()
{
deque <used*> my_queue;
my_queue.resize(6);
used* object = new used; <-------marked line
for(unsigned int i=0; i<my_queue.size(); i++)
{
my_queue.push_back(object);
}
cout << my_queue[5] << endl; //Should give 0
my_queue[0]->member=1000;
cout << my_queue[0]->member << endl; //1000
}
in main file(I have only read access),
#include "the_used.h"
#include <iostream>
#include <stdlib.h>
#include <sstream>
using namespace std;
int main()
{
the_used *object = new the_used();
}
Actually, I am getting undefined reference to used::used() at the marked line. What seems to be the problem?
I have tried to use the same for a vector as well but to no avail.
I am not allowed to make changes to the 'int main(){}'.
Any help would be highly appreciated.
Your class declaration doesn't declare any constructor or destructor:
class used
{
public:
int member=0;
};
But in your cpp file you define them. Your compiler should complain already here:
#include "used.h"
used::used()
{
}
used::~used()
{
}
You must declare constructor and destructor in your class:
class used
{
public:
used();
~used();
int member=0;
};
Then here:
my_queue.resize(6);
you will actually create 6 pointers that will be initialized to nullptr. Maybe you're aware of that, since you expect my_queue[5] to return 0.
Then in your loop, everytime you do this:
my_queue.push_back(object);
you will increase the size of my_queue by one, thus make your loop run forever.
Apart from that: Do. Not. Do. using namespace std;. Ever.
I need to expose some unmanaged data using CLIWrapper.
Let's say I have a vector, but there is no null-characters in the middle of the vector (for sure). What would be the best way to do this type of assigment/marshalling?
And just in case.... How whould the same operation looks like if I do assigning from vector to cli::array?
You can directly use the String class constructor. Like this:
#include "stdafx.h"
#include <vector>
using namespace System;
int main(array<System::String ^> ^args)
{
std::vector<wchar_t> example;
example.push_back('x');
String^ str = gcnew String(&example[0], 0, example.size());
Console::WriteLine(str);
return 0;
}
I made a DLL with a function named "render()" and I want to load it dynamically to my application, but GetProcAddress cannot find it. Here's the DLL .h:
#ifdef D3D_API_EXPORTS
#define D3D_API_API __declspec(dllexport)
#else
#define D3D_API_API __declspec(dllimport)
#endif
D3D_API_API void render();
And here's DLL .cpp:
#include "stdafx.h"
#include "D3D_API.h"
#include <iostream>
D3D_API_API void render()
{
std::cout << "method called." << std::endl;
}
Here's the application that tries to use that function:
#include "stdafx.h"
#include <windows.h>
#include <iostream>
int _tmain(int argc, _TCHAR* argv[])
{
HINSTANCE myDLL = LoadLibrary( L"D3D_API.dll" );
if (myDLL == NULL) {
std::cerr << "Loading of D3D_API.dll failed!" << std::endl;
}
typedef void (WINAPI *render_t)();
render_t render = (render_t)GetProcAddress( myDLL, "render" );
if (render == NULL) {
std::cerr << "render() not found in .dll!" << std::endl;
}
return 0;
}
My goal is to make a 3D engine that supports both D3D and OpenGL through their own .DLLs using a unified API. I looked at the .dll in notepad and there was a string "render".
The function you export is treated as a C++ function (because of *.cpp file extension) and so C++ name mangling is used to decorate the exported function name. If you use the Dependency Walker tool from Microsoft to inspect your created DLL you will see the functions full name.
You can either use that decorated name in your import code or force the compiler to export your function in C style, that is, in its undecorated form that your current import code expects.
You can tell the compiler to do so by adding extern "C" to your functions signature. Something like this:
extern "C" D3D_API_API void render();
Now your import code should work as expexted.
As the comment to the answer says:
using 'extern "C"' will remove any C++ name mangling, but still leaves
C name mangling. In order to export the plain names you should look at
using a .DEF file. See
blogs.msdn.microsoft.com/oldnewthing/20120525-00/?p=7533
You need to add a new file with .DEF extension to your project, with similar to this contents:
LIBRARY "MyRenderLib"
EXPORTS
render
Then in your DLL header you don't use __declspec(dllexport), but only extern "C"
extern "C" void render();