#pragma comment(lib, "libmcrypt.lib")
When the platform is Visual Studio 2012 (v110), it is OK. But, when platform is WindowsApplicationForDrivers8.0, it reports error LNK2019
When I include OpenSSL in my project, I'm getting the same error.
From the MSDN.
The following sample generates LNK2019:
// LNK2019.cpp
// LNK2019 expected
extern char B[100]; // B is not in avilable to the linker
int main() {
B[0] = ' ';
}
LNK2019 can also occur when you declare but do not define a static data member. The following sample generates LNK2019:
// LNK2019b.cpp
// LNK2019 expected
struct C {
static int s;
};
// Uncomment the following line to resolve.
// int C::s;
int main() {
C c;
C::s = 1;
}
Please go to the MSDN link for full explanation
http://msdn.microsoft.com/en-us/library/799kze2z(v=vs.80).aspx
Related
By some reason MSVC DO NOT compile boost serialization example with the following code:
class MyName
{
public:
MyName(std::string _name, std::string _family_name)
:name{ _name }, family_name{ _family_name }
{ }
private:
friend class boost::serialization::access;
template<class Archive>
void serialize(Archive & ar, const unsigned int version)
{ ar & name; ar & family_name; } std::string name; std::string family_name;
};
int main()
{
// create and open a character archive for output
std::stringstream ofs;
// save data to archive
{
MyName my_name("MyName", "FamilyName");
boost::archive::text_oarchive oa(ofs);
// write class instance to archive
oa << my_name;
// archive and stream closed when destructors are called
}
// save data to archive
{
MyName my_name("afsf", "dgsass");
boost::archive::text_iarchive oa(ofs);
// write class instance to archive
oa >> my_name;
// archive and stream closed when destructors are called
}
return 0;
}
I get the follwing error:
Severity Code Description Project File Line Suppression State
Error LNK2019 unresolved external symbol "public: __thiscall boost::archive::archive_exception::archive_exception(enum boost::archive::archive_exception::exception_code,char const *,char const *)" (??0archive_exception#archive#boost##QAE#W4exception_code#012#PBD1#Z) referenced in function "protected: void __thiscall boost::archive::basic_text_iprimitive<class std::basic_istream<char,struct std::char_traits<char> > >::load<unsigned int>(unsigned int &)" (??$load#I#?$basic_text_iprimitive#V?$basic_istream#DU?$char_traits#D#std###std###archive#boost##IAEXAAI#Z) cpp11_cpp14_cpp17 D:\Projects_Programing\__Testing\cpp11_cpp14_cpp17\cpp11_cpp14_cpp17\cpp11_cpp14_cpp17.obj 1
But when I compiled it in release mode.
I have read that it could happen due to MSVC STRICT mode, but I have tried and it does not work neither.
Have anybody got such error ?
I have figured out the reason of this error.
It happens when I tried to compile with flag /Za (means zero extension from MSVC for C++).
When I removed this flag my code compiles succesfully.
#lakeweb Thank you for your help and support !!
Unfortunately I do not understand why some extensions from MSVC does allow to compile Boost, but without extentions it does not compile. It is very strange !!
Maybe it is either the bug on Boost side or on MSVC side.
Any assumption ?
I was trying to poll available devices on a Windows machine by this code example from Microsoft. But there are link errors that relates to _main().
#include <stdio.h>
#include <windows.h>
#include <setupapi.h>
#include <devguid.h>
#include <regstr.h>
int main( int argc, char *argv[ ], char *envp[ ] )
{
HDEVINFO hDevInfo;
SP_DEVINFO_DATA DeviceInfoData;
DWORD i;
// Create a HDEVINFO with all present devices.
hDevInfo = SetupDiGetClassDevs(NULL,
0, // Enumerator
0,
DIGCF_PRESENT | DIGCF_ALLCLASSES );
if (hDevInfo == INVALID_HANDLE_VALUE)
{
// Insert error handling here.
return 1;
}
// Enumerate through all devices in Set.
DeviceInfoData.cbSize = sizeof(SP_DEVINFO_DATA);
for (i=0;SetupDiEnumDeviceInfo(hDevInfo,i,
&DeviceInfoData);i++)
{
DWORD DataT;
LPTSTR buffer = NULL;
DWORD buffersize = 0;
//
// Call function with null to begin with,
// then use the returned buffer size (doubled)
// to Alloc the buffer. Keep calling until
// success or an unknown failure.
//
// Double the returned buffersize to correct
// for underlying legacy CM functions that
// return an incorrect buffersize value on
// DBCS/MBCS systems.
//
while (!SetupDiGetDeviceRegistryProperty(
hDevInfo,
&DeviceInfoData,
SPDRP_DEVICEDESC,
&DataT,
(PBYTE)buffer,
buffersize,
&buffersize))
{
if (GetLastError() ==
ERROR_INSUFFICIENT_BUFFER)
{
// Change the buffer size.
if (buffer) LocalFree(buffer);
// Double the size to avoid problems on
// W2k MBCS systems per KB 888609.
buffer = LocalAlloc(LPTR,buffersize * 2);
}
else
{
// Insert error handling here.
break;
}
}
printf("Result:[%s]\n",buffer);
if (buffer) LocalFree(buffer);
}
if ( GetLastError()!=NO_ERROR &&
GetLastError()!=ERROR_NO_MORE_ITEMS )
{
// Insert error handling here.
return 1;
}
// Cleanup
SetupDiDestroyDeviceInfoList(hDevInfo);
return 0;
}
For some reasons, there are link errors:
1>device.obj : error LNK2019: unresolved external symbol __imp__SetupDiDestroyDeviceInfoList#4 referenced in function _main
1>device.obj : error LNK2019: unresolved external symbol __imp__SetupDiGetDeviceRegistryPropertyW#28 referenced in function _main
1>device.obj : error LNK2019: unresolved external symbol __imp__SetupDiEnumDeviceInfo#12 referenced in function _main
1>device.obj : error LNK2019: unresolved external symbol __imp__SetupDiGetClassDevsW#16 referenced in function _main
1>c:\users\visual studio 2010\Projects\usb\Debug\usb.exe : fatal error LNK1120: 4 unresolved externals
What they are about? There is no _main() at all.
First thing first, the linker errors are not about missing main, but about other functions that are referenced (called) from main.
The functions you mentioned in linker errors are from library: Setupapi.lib, and you need to include it in Linker settings (Input) of your project.
Why did it worked on VS re-open?
Probably simply because you changed the configuration (by mistake). For example from Win32 to x64, and/or from Debug to Release (or any combination) of these. The other configuration didn't have reference to this library added.
why would the following sniplet
#include <atlcom.h>
...
class FormRegionWrapper;
...
// Errorsource :
typedef IDispEventSimpleImpl
<2, FormRegionWrapper, &__uuidof(FormRegionEvents)>
FormRegionEventSink;
will give me the following errors:
// Error ouput:
error C2143: syntax error : missing ';' before '<'
error C4430: missing type specifier - int assumed.
Note: C++ does not support default-int
?!?
(The sniplet is taken from here : Building a C++ Add-in for Outlook 2010 ). My environment : MS Visual Studio 2012 Professinal, and Windows 7-64.
PS 1: Here what the help says about the IDispEventSimpleImpl :
// Help IDispEventSimpleImpl Class : This class provides implementations of
// the IDispatch methods, without getting type information from a type library.
// template <
// UINT nID,
// class T,
// const IID* pdiid
// >
// class ATL_NO_VTABLE IDispEventSimpleImpl :
// public _IDispEventLocator<nID, pdiid>
//
// Requirements
// -------------------
// Header: atlcom.h
Have you included atlcom.h so that the template IDispEventSimpleImpl is defined? Are the declarations of other classes (I assume written by you) used in the template declaration available? And i don't think that forward definition of FormRegionWrapper is enough, can you try and include the declaration of that class, so that template sees it?
UPDATE
Not sure if this will help much, but I replaced the source of FormRegionWrapper.h with the colde below (example from the MSDN page on IDispEventSimpleImpl:
#pragma once
#include "stdafx.h"
#include <vector>
#include <algorithm>
_ATL_FUNC_INFO Event1Info1 = { CC_CDECL, VT_EMPTY, 1, { VT_I4 } };
class CEventHandler;
typedef IDispEventSimpleImpl <1234, CEventHandler, &__uuidof(IDispatch)>
DummySink;
class CEventHandler : public DummySink
{
public:
BEGIN_SINK_MAP(CEventHandler)
SINK_ENTRY_INFO(1234, __uuidof(IDispatch), 1, OnEvent1, &Event1Info1)
END_SINK_MAP()
void __stdcall OnEvent1(LONG l)
{
//ATLASSERT(l == 445533);
if (l != 445533)
OutputDebugString(L"l is not 445533\n");
}
HRESULT Advise1234(IUnknown * punk) {
return IDispEventSimpleImpl<1234, CEventHandler, &__uuidof(IDispatch)>::DispEventAdvise(punk);
}
};
If this works, you can safely assume that the template is being included correctly.
Add this line after the #include directives in FormRegionWrapper.h:
using namespace ATL;
I am upgrading my project from VS 6 to VS 2010, while building in release mode, I am facing the below error.
1>Creating library .\Release\JfFrpF32.lib and object .\Release\JfFrpF32.exp>
1>FLD_.obj : error LNK2019: unresolved external symbol __imp__debugf referenced in function "int __cdecl fld_new(char *,unsigned char,unsigned char,short,char,char,unsigned char,short,char,double,double,short,char *,char,short,short)" (?fld_new##YAHPADEEFDDEFDNNF0DFF#Z)
1>Release/JfFrpF32.dll : fatal error LNK1120: 1 unresolved externals
1>
1>Build FAILED.
Please help me .. thanks in advance..
Common problems that cause LNK2019 include:
The declaration of the symbol contains a spelling mistake, such that,
it is not the same name as the definition of the symbol.
A function was used but the type or number of the parameters did not
match the function definition.
The calling convention (__cdecl, __stdcall, or __fastcall) differs on
the use of the function declaration and the function definition.
Symbol definitions are in a file that was compiled as a C program and
symbols are declared in a C++ file without an extern "C" modifier. In
that case, modify the declaration.
For More Information See Here
In my case, even though I used extern "C", I got the unresolved symbol error.
The hpp was
extern "C"
{
class A
{
public:
void hi();
};
A* a;
DECLDIR int Connect();
}//extern
and the cpp was
#include "DatabasePlugin.hpp"// Include our header, must come after #define DLL_EXPORT
extern "C" // Get rid of name mangling
{
DECLDIR int Connect()
{
a = new A();
a->hi();
return 0;
}//Connect
}//extern
The problem was that I had not created an implementation for the hi() function. Adding it solved the problem. Like this:
extern "C" // Get rid of name mangling
{
void A::hi() {}
DECLDIR int Connect()
{
a = new A();
a->hi();
return 0;
}//Connect
}//extern
Having to declare Hi() before Connect() may also be significant.
I am trying to create a simple C++ class and a Matlab mex file. My code is as follows:
Matlab: mexTest1.cpp
#include "mex.h"
#include "K:\\My Documents\\Visual Studio 2010\\Projects\\HelloWorld\\HelloWorld\\Class1.h"
/* Input Arguments */
#define X prhs[0]
/* Output Arguments */
#define RESULT plhs[0]
void mexFunction( int nlhs, mxArray *plhs[],
int nrhs, const mxArray *prhs[] ){
/* Initialize input and output pointers
// Inputs */
double *x;
/* Outputs */
double r;
double *result;
mwSize m,n;
m = mxGetM(X);
n = mxGetN(X);
/* Create a matrix for the return argument */
RESULT = mxCreateDoubleMatrix(1, 1, mxREAL);
/* Assign pointers to the various parameters */
result = mxGetPr(RESULT);
x = mxGetPr(X);
/* Do the actual computations in a subroutine */
Class1 c1(2, 15.0);
r = c1.product();
result[0] = r;
return;
}
Class1.h:
#pragma once
#include <string> // Standard string class in C++
class Class1
{
public:
int a;
double b;
public:
Class1(const int& a, const double& b);
//virtual ~Class1();
void print() const;
double product() const;
};
Class1.cpp:
#include "stdafx.h"
#include <iostream>
#include "Class1.h"
Class1::Class1(const int& a, const double& b){
Class1::a = a;
Class1::b = b;
}
void Class1::print() const{
std::cout << "a=" << Class1::a << " * b=" << Class1::b << " = " << Class1::product() << std::endl;
}
double Class1::product() const{
return a*b;
}
Running the Matlab command mex mexTest1.cpp gives the error messages:
Creating library C:\DOCUME~1\K\LOCALS~1\TEMP\MEX_RH~1\templib.x and object C:\DOCUME~1\K\LOCALS~1\TEMP\MEX_RH~1\templib.exp
mexTest1.obj : error LNK2019: unresolved external symbol "public: double __thiscall Class1::product(void)const " (?product#Class1##QBENXZ) referenced in function _mexFunction
mexTest1.obj : error LNK2019: unresolved external symbol "public: __thiscall Class1::Class1(int const &,double const &)" (??0Class1##QAE#ABHABN#Z) referenced in function _mexFunction
mexTest1.mexw32 : fatal error LNK1120: 2 unresolved externals
C:\PROGRA~1\MATLAB\R2011A\BIN\MEX.PL: Error: Link of 'mexTest1.mexw32' failed.
??? Error using ==> mex at 208
Unable to complete successfully.
Can anyone help me fix this problem?
Thanks.
The linker is telling you that in trying to construct an executable, it wasn't supplied with an object file that contains Class1::product and Class1::Class1. That's because those functions would be supplied by compiling Class1.cpp, which your command line doesn't ask for.
You should use the syntax of mex for multiple files: mex mexTest1.cpp Class1.cpp
Your linker is unable to find deinitions(bodies) Class1 methods (constructor and product). This may be due to
You haven't provided any definition(body)
The definitions are in a lib file which you forgot to link to