I'm writing CPP unit test and the code of one used lib file references a procedure in dll.
I would like to remove this lib and the dll from the project.
I have made replacement methods for methods from the lib file, but there is one method which is imported from dll:
error LNK2019: unresolved external symbol "__declspec(dllimport) class CX * __cdecl CreateX(wchar_t const *)" (__imp_?....) referenced in function "...."
Is there a way how to declare a local function to link this with my code instead of dll import?
Just create a stub implementation of the missing file in your project. This will remove the linker error.
Related
I'm currently using Microsoft Unit Testing Framework for C++ and have been following this guide:
https://learn.microsoft.com/en-us/visualstudio/test/writing-unit-tests-for-c-cpp?view=vs-2019
However, when trying to create a test project under the same solution as the project I am testing I can't I keep getting the linker error
LNK2019 unresolved external symbol "public: void __cdecl SLL<int>::add(int)" (?add#?$SLL#H##QEAAXH#Z) referenced in function "public: void __cdecl A1272UnitTest::A1272UnitTest::TestMethod1(void)" (?TestMethod1#A1272UnitTest#1#QEAAXXZ)
The problem I am trying to use a method definition inside of the "q1a.cpp" file under the project I am testing.
I have tried following this guide
https://learn.microsoft.com/en-us/visualstudio/test/how-to-use-microsoft-test-framework-for-cpp?view=vs-2019#object_files
In order to link the obj files but it was of no avail.
This is what my
solution directory looks like
I have created Regular DLLs Dynamically Linked to MFC.
in before build dll in dll project i used add another class. this class provide more method of constructor overloading.
Then I build dll successfully after i used this lib and dll file include project and then go to build and get linker error when using constructor overloading class
My Class Name: Object
Error 11 error LNK2001: unresolved external symbol "public: __thiscall AvinashiAMF::Object::~Object(void)" (??1Object#AvinashiAMF##QAE#XZ) BuleCappServiceUseDynamicDllDlg.obj
Error 10 error LNK2001: unresolved external symbol "public: __thiscall AvinashiAMF::Object::Object(enum AvinashiAMF::ObjectType,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >)" (??0Object#AvinashiAMF##QAE#W4ObjectType#1#V?$basic_string#DU?$char_traits#D#std##V?$allocator#D#2##std###Z) BuleCappServiceUseDynamicDllDlg.obj
Error 12 fatal error LNK1120: 2 unresolved externals D:\Test Aplications\Visual Studio 2008\Projects\BuleCappServiceUseDynamicDll\Release\BuleCappServiceUseDynamicDll.exe
You're probably not exporting your class. See here http://msdn.microsoft.com/en-us/library/81h27t8c.aspx
Also, a nice tool to check for this kind of issues is depends.exe, included with Visual Studio, which allows you to check for exported and imported symbols.
There are two significantly different dynamic link libraries: implicitly linked and explicitly linked.
In short, implicitly linked is linked at the compile time. You need an import library to link with(.lib), header file with functions prototypes and properly usage of the dllexport and dllexport or use .def file.
dllexport/dllexport are easier to use in this case. System takes care of loading libraries (DLLs).
Explicit linking is a runtime linking. You do not need any import library or headers. You need to know what is the function signature. You have to explicitly call LoadLibrary and GetProcAddress to call the function.
To see how to properly create macros for export/import create empty Win32 project select DLL and make sure the Export symbols check box is checked.
In the main header file you will see explanation how to use macros for import/export.
I want to create unit tests for a Visual C++ project. I tried following these MSDN instructions. I've found pages where they differentiate between unmanaged/mixed/pure code, but I don't fully understand those concepts. My code doesn't use .NET and would likely compile under MinGW with a few code adjustments.
My main project builds an executable, so I followed the steps under To reference exported functions from the test project. For starters I got different project options:
I went with Native Unit Test Project. I added a reference to my main project and I set Include Directories to $(SolutionDir)\Cubes;$(IncludePath). I wrote my code and got this when compiling:
1>Creating library C:\Users\Pieter\Dropbox\Unief\TTUI\TTUIproject\Cubes\Debug\CubesTest.lib and object C:\Users\Pieter\Dropbox\Unief\TTUI\TTUIproject\Cubes\Debug\CubesTest.exp
1>LayoutTest.obj : error LNK2019: unresolved external symbol "public: __thiscall Room::Room(void)" (??0Room##QAE#XZ) referenced in function "public: void __thiscall CubesTest::LayoutTest::NumOfRoomsConsistency(void)" (?NumOfRoomsConsistency#LayoutTest#CubesTest##QAEXXZ)
1>LayoutTest.obj : error LNK2019: unresolved external symbol "public: __thiscall Layout::Layout(class Room *,int)" (??0Layout##QAE#PAVRoom##H#Z) referenced in function "public: void __thiscall CubesTest::LayoutTest::NumOfRoomsConsistency(void)" (?NumOfRoomsConsistency#LayoutTest#CubesTest##QAEXXZ)
1>LayoutTest.obj : error LNK2019: unresolved external symbol "public: void __thiscall Layout::add(int,int,class Room *)" (?add#Layout##QAEXHHPAVRoom###Z) referenced in function "public: void __thiscall CubesTest::LayoutTest::NumOfRoomsConsistency(void)" (?NumOfRoomsConsistency#LayoutTest#CubesTest##QAEXXZ)
1>LayoutTest.obj : error LNK2019: unresolved external symbol "public: void __thiscall Layout::clear(int,int,bool)" (?clear#Layout##QAEXHH_N#Z) referenced in function __catch$?NumOfRoomsConsistency#LayoutTest#CubesTest##QAEXXZ$0
1>C:\Users\Pieter\Dropbox\Unief\TTUI\TTUIproject\Cubes\Debug\CubesTest.dll : fatal error LNK1120: 4 unresolved externals
If I'm not mistaken, this means that the compiler finds the header files, but not the source files. What am I missing?
Here is a step-by-step description on how to add an EXE as an unit-test target.
The key point is to "export" the functions/classes you want to test... You can download the complete sample here: http://blog.kalmbachnet.de/files/CPP_UnitTestApp.zip (I did not change any project settings, so all changes you can see in the source-code; of course, some parts can be made in the project settings).
Create a Win32 Application (Console or MFC or Windows, does not matter); I created a console project called CPP_UnitTestApp:
Add a function you want to test (you can also add classes). For example:
int Plus1(int i)
{
return i+1;
}
Add a header file for the functions you want to test: CPP_UnitTestApp.h
Put the declaration of the methods into the header file, and also export these functions!
#pragma once
#ifdef EXPORT_TEST_FUNCTIONS
#define MY_CPP_UNITTESTAPP_EXPORT __declspec(dllexport)
#else
#define MY_CPP_UNITTESTAPP_EXPORT
#endif
MY_CPP_UNITTESTAPP_EXPORT int Plus1(int i);
Include this header file in the main-cpp (here CPP_UnitTestApp.cpp) and define the EXPORT_TEST_FUNCTIONS before including the header:
#define EXPORT_TEST_FUNCTIONS
#include "CPP_UnitTestApp.h"
Now add a new project (Native unit test project: UnitTest1)
Include the header and the lib to the "unittest1.cpp" file (adopt the paths as you want):
#include "..\CPP_UnitTestApp.h"
#pragma comment(lib, "../Debug/CPP_UnitTestApp.lib")
Go to the project settings of the test project add add a reference to the "UnitTest1" project (Project|Properties|Common Properties|Add New Reference...: Select under "Projects" the "CPP_UnitTestApp"-Project)
Create the unit test function:
TEST_METHOD(TestMethod1)
{
int res = Plus1(12);
Assert::AreEqual(13, res);
}
Run your unit test ;)
As you can see, the main point was to export the function declaration! This is done via __declspec(dllexport) even if it is an EXE.
As I said, the demo project can be downloaded here: http://blog.kalmbachnet.de/files/CPP_UnitTestApp.zip
I'm trying to build a solution in Visual C++ where I have a front-end project that references a DLL project that I created. In the DLL project I link to a static library (that I have not written) that has static objects and definitions. Everything builds fine but I have linking problems.
I have a couple of questions. First, I should only get unresolved symbols for objects that I reference in the front-end that are not exported, right? I want the DLL to be the only interface to the static library and do not directly reference any part of it in the front-end, and yet I get a number of unresolved symbols from this library. There symbols seem to be #included and at least some not directly linked by the DLL project. I suspect it has to do with the static declarations in the static lib but how can I deal with these?
Some of the unresolved symbol errors:
2>AnalysisVis.obj : error LNK2001: unresolved external symbol "public: __thiscall SharkException::SharkException(char const *,int,char const *)" (??0SharkException##$$FQAE#PBDH0#Z)
2>AnalysisVis.obj : error LNK2001: unresolved external symbol "public: static class Bernoulli Rng::coinToss" (?coinToss#Rng##2VBernoulli##A)
2>AnalysisVis.obj : error LNK2001: unresolved external symbol "public: virtual bool __thiscall ChromosomeT<bool>::operator<(class Chromosome const &)const " (??M?$ChromosomeT#_N##$$FUBE_NABVChromosome###Z)
The exported symbols are mangled. If the static lib was compiled using a different compiler (or compiler version) than the one you are using, it is possible that the symbols your application is expecting to see were defined in the static lib using a different name mangling scheme. You can use the following command to get the name mangling used in the static lib and then compare it to the one in the error message:
>pushd <path_to_msvc_dir>\Microsoft Visual Studio X.0\VC\bin
>dumpbin /all [static_lib_path] > out.txt
>type out.txt | find /I "SharkException"
>type out.txt | find /I "coinToss"
>type out.txt | find /I "ChromosomeT"
BTW, does the DLL that uses the static lib compiles cleanly with the same compiler your application/solution does?
I just have a problem that I have been trying to fix for the longest time.
I have a static library project in visual c++, and I want another project to be able to link to it. Up until now, I have simply been adding a reference to the static library project, which automatically links the library.
I want to be able to link to the library using only the header files and the .lib file. However, I get a "Unresolved external symbol" error.
I thought I was doing it right - I specified the include directory, the library directory, and went into the linker input properties and provided the lib as an additional dependency.
I am able to reference other static libraries this way (like SDL), so why do I get errors when I try to reference mine?
Thanks for the help.
Is the problem that its not referencing the actual lib file, or is something within the lib itself?
These are the error messages I get:
Error 2 error LNK2019: unresolved external symbol "public: void __thiscall XEngine::XCore::XScreen::init(class XEngine::XCore::XGame &)" (?init#XScreen#XCore#XEngine##QAEXAAVXGame#23##Z) referenced in function "void __cdecl XEngine::XEngineInit(class XEngine::XCore::XScreen &,class XEngine::XCore::XGame &)" (?XEngineInit#XEngine##YAXAAVXScreen#XCore#1#AAVXGame#31##Z) C:\Users\Xander Masotto\Documents\Visual Studio 2010\Projects\Pong\Pong\source.obj Pong
Error 3 error LNK2019: unresolved external symbol "public: __thiscall XEngine::XCore::XScreen::~XScreen(void)" (??1XScreen#XCore#XEngine##QAE#XZ) referenced in function "void __cdecl XEngine::XEngineInit(class XEngine::XCore::XGame &)" (?XEngineInit#XEngine##YAXAAVXGame#XCore#1##Z) C:\Users\Xander Masotto\Documents\Visual Studio 2010\Projects\Pong\Pong\source.obj Pong
Error 4 error LNK2019: unresolved external symbol "public: __thiscall XEngine::XCore::XScreen::XScreen(void)" (??0XScreen#XCore#XEngine##QAE#XZ) referenced in function "void __cdecl XEngine::XEngineInit(class XEngine::XCore::XGame &)" (?XEngineInit#XEngine##YAXAAVXGame#XCore#1##Z) C:\Users\Xander Masotto\Documents\Visual Studio 2010\Projects\Pong\Pong\source.obj Pong
Make sure that you are exporting the functions, classes, and variables in your library that you want exposed to other applications (i.e. your dll or exe). By default they are not exposed.
The ground work to do this is typically layed out when you create the project for your library.
#ifdef TESTLIB_EXPORTS
#define TESTLIB_API __declspec(dllexport)
#else
#define TESTLIB_API __declspec(dllimport)
#endif
With the code above generated during project creation there are only two more things for me to do to expose functions,classes, or variables:
1) Make sure that I have TESTLIB_EXPORTS defined as a preprocessor. Project settings: C++/Preprocessor/PreprocessorDefinitions
2) Use the TESTLIB_API define on each function,class, or variable i want exposed:
class TESTLIB_API Order {
void doSomething();
};