I'm trying to integrate in a pre-existing code a third part library which have been given to me with three files (.dll, .lib and .exe) plus a header file .h .
I tried the following steps:
- include the header file adding also the directory in the include directories
- add the library .lib to the linker inputs additional dependancy
- move everything to the same folder of the solution
I'm using visual studio 2017. and all the code seems to compile with no errors, but when I try to access the functions of this library I got a message saying definition not found. Unfortunately I would like to access them to use only part of code that I need not the entire function.
Do I forget something / have to do something else?
The steps for integration third-party dynamic libraries with VC++:
1) Change project configuration linker settings to dynamic runtime ( /MD )
2) Confirm platform of the third party (x86 / x64) and set accordingly in the vc++ project.
3) Include the header files. No compilation errors means that the header files are correctly included by the compiler.
4) Include the *.lib with path in the additional libraries; once correctly set, the project will build successfully. Failing this step will give you - 'symbol not found', 'definition not found', and linker errors
5) Copy dll files to your application folder, failing which the .exe will not launch. The dll files also has to conform to x86/x64 the project architecture/
Related
I'm having trouble trying to get v8 working with visual studio 2019.
I have followed the compiling guide on v8.dev and built it on windows.
I have followed [this]Google V8 - Neither v8.dll nor v8.dll.lib getting built in release mode answer to obtain .dll and .lib files.
Now I'm stuck. I tried to build the examples they show on the official site (https://chromium.googlesource.com/v8/v8/+/branch-heads/6.8/samples/hello-world.cc) but I get all sorts of errors.
From what I understand, I need .dll, .lib and .h files. I have them, but I'm not able to use them correctly in visual studio.
I have tried adding the header files under include directories and .lib files under Linker > Input > Additional Dependencies without luck.
There are good chances anyone who has worked with c++ beyond simple console programs will laugh at my ignorance, and I would understand that.
Any help would be very appreciated.
UPDATE
These are the steps i followed to use v8:
1) Created a new c++ console solution
2) Added header directory at Configuration > C/C++ > Additional Include Directories
3) Added dll and v8.dll.lib folder in Configuration > Linker > Input > Additional Dependencies
4) Pasted this (https://chromium.googlesource.com/v8/v8/+/branch-heads/6.8/samples/hello-world.cc) code to my editor
The first type of error I got is E1696: it looks like some headers contain references to other headers with absolute paths and not relative paths.
I fix this by myself making reference paths relative in headers.
Then I get 23 LNK2019 errors:
screeshot
What should I do?
I am trying to create a C++ project in Visual Studio 2013 that has CGAL and Boost (and a couple of other libraries) as dependencies. I preferably like to link to these libraries dynamically. Also, I'd like to link to the "Release" versions of these libraries for performance reasons (not the "Debug" versions).
Starting from an empty C++ project, I added the path to header files of the aforementioned libraries as shown in the image below:
Inside the linker options, I then added the directories that contain the DLL and lib files of the external libraries. (CGAL directory contains CGAL's compiled DLL files along with lib files).
At this point, I have not added a single "lib" file "Additional Dependencies" dialog:
Now something weird is going on and I cannot explain why. If I try to build the project as-is (under the "Debug" configuration), I get a LNK1104 error about the linker not being able to find CGAL-vc120-mt-gd-4.7.lib. I know that the error means I should add the lib file in "Additional Dependencies" dialog...
But wait... WHAT...?!!
How does Visual Studio know how to automatically link against this lib file?! Worse yet, how does it know it needs the "debug" version of the library? (With the gd suffix). Also, how does it know I compiled CGAL with VS2013!!??
At first, I though the project was inheriting properties from some preset property sheets somewhere in my system. But I am certain that's not the case as this behavior shows even with a project created from scratch.
My main question is, how would you force Visual Studio to link against the "Release" version of this library? (eg. CGAL-vc120-mt-4.7.lib)
Side question but related: Am I even linking against the DLL files? How can I be certain that I am in deed doing dynamic linking and not static linking?
This is probably happening due to the #pragma comment(lib) mechanism - eg see What does "#pragma comment" mean?
This is a way of the compiler emitting instructions for the linker so that it can decide between multiple versions of a library depending on the compiler version. In this case it means that it can automatically pick up the correct version of the library (debug vs release, vs2013 vs vs2015, MT vs MD, etc). When you added the explicit reference to the library in Additional Dependencies then it is now trying to look for two files.
So, to fix the problem, remove it from Additional Dependencies and let VS pick the right library. If you are getting the LNK1104 error then it suggests that either the link library path isn't set up correctly, or you don't have the CGAL library file it's looking for. You can increase the verbosity settings for the linker in the Project Options to get more detail about what's happening.
I am working on a project that involves making a dynamic link library, so I want to test it in a console app in Visual Studio.
The DLL is also made in Visual Studio, it doesn't have much, just a few functions in it. I'm not sure if I'm just supposed to include the librarys header in the include directories panel in Properties, or do something else
A lot of people say I'm supposed to add its corresponding .lib file in the Library or Reference directory, but I'm not sure that VS generates a .lib file alongside the DLL. I'm using VS 2015.
I don't have VS in front of me this very moment, but these should be the general steps to set it up:
Properties->Linker->Input: your.lib
Properties->Linker->Additional Library Directories: ../your/bin
Properties->General->Compiler->Additional Include Directories: ../your/include
To build your app, the DLL's API headers must be in the include for the compile-time, it's LIB files in the bin for the link-time. Once you have your app EXE, all you need is the DLL to be in the same folder as your EXE when it executes.
You might also want to add the dll project and the app project into a common solution in VS and add (right click) Project Dependency from the app to the dll. This ensures correct order of building, assuming you are going to build the dll at all.
You can also do what I did.
You can create a Libs directory inside of your Solution directory.
You can then place your .DLL files inside of the Libs directory or some sub-directory inside of Libs
In my case, I added the entire SFML-2.3.2 directory in there, which included the source-code, .lib files, and .dll files.
I did link up what I could in the project properties, but I used Visual Studio's macros to fill in the path name to the Solution directory. Just in case I wanted to put this in version control and work on it from multiple machines.
Then I opened up the Project's Property Page.
Within the property page, I went to Build Events -> Post-Build Event -> Command Line
Within the Command Line, you can add a copy command that will copy any needed files into the same directory as the executable that will need them.
In my case I used: copy "$(SolutionDir)Libs\SFML-2.3.2\bin\*" "$(TargetDir)"
I could have written multiple commands to copy just the individual files that I needed, but I had spent a good three hours trying to get SFML to work without actually installing it.
For learning purposes, i wanted to create a static library, a "package" of the lib files used in opencv to then link it against my app "opencvuser". Doing so, i get tremendous amounts of erros. (LNK2005 and LNK2019)
My Setup:
Project: staticLib
I've created a static library application without precompiled headers.
Under librarian i've put D:\OpenCV248\build\x64\vc10\staticlib as an additional library
directory. And I've specified all available .lib files as additional
dependencies. (opencv_core248d.lib, opencv_imgproc248d.lib, opencv_highgui248d.lib, ...) Source
Project: opencvuser
I've added C:\OpenCV240\build\include as an additional include directory
Then i've listed "staticLib" under "Properties -> References"
What i expect: Now i should get the same functionallity, as i would add the opencv lib files instead of my built staticLib.lib is my expectation correct?
What i've checked so far:
All Projects are x64
Runtime-Library is set in both Projects to "Multi-threaded Debug"
Anyone knows if the Runtime-Library setting on the static libraries are set to "Multi-threaded Debug"?
You are getting those linker errors because the OpenCV libs you are trying to use were statically linked against the CRT. In your project, you are dynamically linking to CRT and these things won't mix. I would recommend that you don't try to create a "package" of all the OpenCV libs and instead just link to the specific libs you need where you need them.
But I am also going to show you how to solve your problem:
You need to recompile OpenCV without statically linking to the CRT.
You can check out the OpenCV documentation for instructions on how to compile OpenCV using CMake and Visual Studio 2010.
When you run CMake, after you pressed the "Configure" button, look for an option called "BUILD_WITH_STATIC_CRT" and disable it. Then you can press "Generate", open the solution with VS2010 and compile OpenCV.
In your VS2010 project, use the following settings:
In the "opencvuser" project configuration, under Librarian, additional library directories you need to add the path to where the .lib files that you built are located. For me, it's in "c:\opencv248\mybuild\lib\Debug\".
Under Additional Dependencies, you need to include all the OpenCV lib files (opencv_core248d.lib, etc). I also needed to include Comctl32.lib and zlibd.lib because if I didn't I would get some linker errors.
Here are the dependencies I put in:
opencv_calib3d248d.lib
opencv_contrib248d.lib
opencv_core248d.lib
opencv_features2d248d.lib
opencv_flann248d.lib
opencv_gpu248d.lib
opencv_haartraining_engined.lib
opencv_highgui248d.lib
opencv_imgproc248d.lib
opencv_legacy248d.lib
opencv_ml248d.lib
opencv_nonfree248d.lib
opencv_objdetect248d.lib
opencv_ocl248d.lib
opencv_photo248d.lib
opencv_stitching248d.lib
opencv_superres248d.lib
opencv_ts248d.lib
opencv_video248d.lib
opencv_videostab248d.lib
Comctl32.lib
zlibd.lib
Also, in the "opencvuser" project you need to add an empty .cpp file. If you don't add this file, the solution will be empty and Visual Studio won't compile it. I just added a file called "dummy.cpp" to the project. That file is completely empty. Don't put a "main()" function in it because it will collide with the main function in the other project and you will get an error.
In the "staticlib" project, under Linker->General, Additional library directories, you need to include the path to the opencvuser.lib file. For me, it's "..\debug". Also, under Linker->Input, Additional Dependencies, you need to add the "opencvuser.lib" file.
Set project dependencies
You also need to make sure that the projects are built in the right order (first opencvuser, then staticlib). To do this, right-click on the solution and choose Properties. In that window, under Common Properties->Project dependencies, make sure that "opencvuser" does not have a dependency on "staticlib", but "staticlib" must have a dependency on "opencvuser".
That's it, now your project should work. Here are the contents of the two files, and the project running.
I'm trying to understand what exactly all of these are and how they relate to each other (and most importantly, how to install them).
From what I've read, LIBs are libraries linked during the compilation of my project and DLLs are libraries linked during the runtime of my project.
So for me to use a LIB, I have to have the actual .LIB file somewhere in my computer, go to Project -> Properties -> VC++ Directories and add the path to the file in the Library Directories, and after this I have to go to Linker -> Input -> Additional Dependencies add the .lib name in there, and finally I need to type #include in my code, right?
So, some questions:
When I finish and build the release of my program, will the .exe only run if the target platform has the .lib installed in their PC as well? If yes, what steps do I need to do to make sure the .lib goes with the .exe?
When I get the source of a open source project, if I add them (using Add Existing Item...) to my project, can I use them just by using #include as if the files were mine and it would be the same as having the .lib installed? Or do I need to install the .lib file and still use these source files?
I have a project using OpenGL and I linked to glew32.lib, but I don't have the lib or any new directory added in the VC++ Directories, so I think this means I must've installed the .lib in the system folder or somewhere where the Visual Studio won't ask for another directory, should I worry about this when releasing a project?
How the above questions relate to DLLs and is there any reason why should I use DLLs over LIBs or the other way around?
I'm starting to use more and more libraries and I noticed I just dragged, copied and included it everywhere so I could use them but never really understood how they "fit" in the project. Especially those open source libraries where they provide so many files and I don't really know what to do with them...
You don't need to have LIB files along with your EXE file for running in another computer, LIB files are static files and DLL files are dynamic. So when you compile all static codes will be included in your EXE file, but DLL files will be loaded and used dynamically in runtime, so you just need to have your DLL files with your EXE file. This way, your code will work and run properly in other computers.
Just adding another project is not enough, you need to compile them and generate LIB files out of them. Then you add the generated LIB file to your final project and include external projects in your final binary. If you are compiling multiple projects together in a solution, you'll need to set project build order in solution properties in VS.
No, that's OK. It seems you've put LIB files in right folder and you don't need to have LIB file with your EXE file to run it in other computers.
DLLs are dynamic libraries, so you need to have them with your application. Installers usually install EXE files with DLL files in the same folder, so your app will run properly, but no need to include LIB files at all.
Also you can include LIB files like this:
#pragma comment(lib, "glew32.lib")
So you don't need to do it in project settings, but assuming you have your LIB file in "Library Directories" path.
Using DLL files can be done in two ways:
One is linking your application to DLL file and having DLL file's function entry in your EXE file's import table:
like using
#include <windows.h>
then
GetWindowsDirectory(windir, MAX_PATH);
So you'll have GetWindowsDirectory API entry in your EXE file's Import Table.
Also you can do it dynamically:
hinstDLL = LoadLibrary("kernel32.dll");
if (hinstDLL != NULL)
{
func_GetWindir = (DLLPROC) GetProcAddress(hinstDLL, "GetWindowsDirectoryA");
...
There is not much difference, only difference is:
In first method, as it's in your EXE file's Import Table, if there was no kernel32.dll or there was no GetWindowsDirectory entry in kernel32.dll, your EXE will not run at all, it will show a critical error and will not run. But in dynamic way (second way), your app will run, but as soon as your code try to use GetWindowsDirectoryA API, it will fail. You will have 0x00 in func_GetWindir. If you attempt to call it, then program will crash.