I'm using C++ and visual studio 2015. I've created 2 projects in 1 solution. The first project is a static library and the other a DLL. I want to include one header file from the static library to use it in the DLL. I tried specifying the path to the header file with - Project->Properties->C/C++ -> General -> Additional include directories but it doesn't work. When I try to include the header file I get a red underline saying "cannot open source file "SomeHeaderFile.h".
Thanks for the help.
Thanks for the tips but I found out how to make it work. The DLL is in a extra folder. All I had to do was #include "../../TheHeaderFileThatISpentHoursTryingToGet.h". I deleted the reference in the additional include directories path and it still works. I always thought that it made sense for files from different projects in the same solution to be accessible throughout all the projects. Thanks again.
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I am a beginner on C++ and trying to learn about including libraries, and I haven't found documentation about it.
What are the ways of including libraries to a C++ project (Visual Studio). How do I implement them and which is the best way?
I was trying to include the SQLite library to a project. I tried to:
Include the header file in the include folder of the Visual Studio installation folder. It did appear in the External dependencies of my project, so I can do #include <sqlite3.h> without problems, but I don't know where I should put the implementation (a C file) and how to link it (is it in the linker>Input>Additional dependencies?).
Is it necessary that in order to include a library the file should be a .lib? Because I can't find the .lib for SQLite 3, do I have to include it in the lib folder of my Visual Studio installation?
Note: I am interested on the management of including a library in general. The SQLite 3 part is only because I took it as an example in order to learn how to add them.
A library is added in two steps
Adding headers path to the project
Adding .lib reference
In the first step, you must specify in the project where library headers are header. Usually, the path is specified in the project properties -> C++ -> Additional include directories, and them including files with relative paths.
In the second step you must specify in properties->linker the path where libraries (.lib) are located and the name of the library. With this Visual Studio is able to link the project properly.
go to project add existing item you must then select from the browse screen the .lib file you wish to add. and BINGO it is there!
best wishes
david
I have a Visual Studio C+++ project, and in the project I have some header files I want to get via the include directories setting on the project properties.
As far as I know that's all set up correctly. I've added the folder path which contains the files and the 3 files appear in the external dependencies folder under my project in Visual Studio.
The problem is that:
when I write the include "xyz.h" for one of the three files, I get "can not find file blah blah" error. This only occurs for one of the three. The other two work fine and I can include them just fine. They are all just basic headers.
Does anyone have any idea why one of my files would fail to work. Thanks
When you setting up the project properties such ad additional include directories, make sure to select "All configurations" in the project properties window. look at the image.
Sorry, the problem was that the file was being used by some background process, so the dll that I was trying to load couldn't open the file.
I know many have asked this question, but following the things suggested hasn't seemed to work for me. So I thought I'd ask for help, as I'm obviously missing something.
I've spent the past couple days writing some code that uses the boost library that allows me to open text files, translate the text into a usable data format, and save the data as a text file when I'm done with it. I built it specifically to be extendable to deal with different datatypes (specifically any object or class I make down the line) so that I could link to it as a library in my project as I do other libraries.
However, even after compiling it into a lib and adding the directory of the lib to the "Additional Include Directories", I get an unresolved external error whenever I try to include one of the header files in the library. I've also tried putting the direct path to it under Additional Dependencies (as well as just the library name with the path to the directory set in Additional Include Directories and Additional Library Directories. I also tried it with only one of those on at a time and it still failed).
Is there something I'm missing? How can I compile this code I'd like to reuse and link to it in new projects without copying the cpp and h files into my solution every time? Would a DLL work better/easier? If so, how would I go about compiling it as a dll and linking to it?
Thanks for reading this wall of text. Any help you could provide would be great.
Ok. While it's not the exact solution I was going for, I managed to figure this out. For anyone running into this problem, there's a wonderful tutorial that explains how to make DLL files and make use of them (at least on windows, don't have any computers using an alternate OS set up yet to test the DLL on). You can find it here.
http://programmingexamples.wikidot.com/blog:1
The gist of the problem is you need to also keep a copy of the .h file handy to include in your project. (what I did is created a directory on my C drive that holds the libraries I'm making, and in that I have a folder for the .lib files and a folder for the .h files.) Either import the .h file directly into your project directory or add it to your project properties (C++ -> General -> Additional Include Directories ). Make sure for that, you're linking to the directory, not the file itself. In the linker, you need to add your .lib file to the Additional Dependencies section (Linker -> Input -> Additional Dependencies). You can put the whole path here, or you can just put the file name, then tell the program where to find the directory it's in (add the path to the directory to Linker -> General -> Additional Library Directories)
Hope this helps anyone else who managed to miss something that everyone else seems to understand instinctually :P
I have had C++ experience but not MSVC.
What I am trying to do is incorporate a .dll from an open source project into my project. The code is available and I have built it. I have the .dll as well as the .lib which as I understand it is required for C++ projects.
Now unfortunately there is no simple "Add Reference", drop my .dll into an include directory and add that to my solution. I have edited the project property pages, the C/C++ Additional Include Directories option as well as adding the .lib as an additional linker dependency. I have created an include directory for the dll and lib inside my solution tree.
My problem is when I try to include the header files from the documentation, VS output spits out error messages. Now I realize that I am using the dll/lib combo and that the .h files are not present in my solution so how do I add the proper includes? I am using QT toolkit also which is working but how I add the other header / dll from the open source library eludes me.
Can someone please point me in the right direction.
You need to do a couple of things to use the library:
Make sure that you have both the *.lib and the *.dll from the library you want to use. If you don't have the *.lib, skip #2
Put a reference to the *.lib in the project. Right click the project name in the Solution Explorer and then select Configuration Properties->Linker->Input and put the name of the lib in the Additional Dependencies property.
You have to make sure that VS can find the lib you just added so you have to go to the Tools menu and select Options... Then under Projects and Solutions select VC++ Directories,edit Library Directory option. From within here you can set the directory that contains your new lib by selecting the 'Library Files' in the 'Show Directories For:' drop down box. Just add the path to your lib file in the list of directories. If you dont have a lib you can omit this, but while your here you will also need to set the directory which contains your header files as well under the 'Include Files'. Do it the same way you added the lib.
After doing this you should be good to go and can use your library. If you dont have a lib file you can still use the dll by importing it yourself. During your applications startup you can explicitly load the dll by calling LoadLibrary (see: http://msdn.microsoft.com/en-us/library/ms684175(VS.85).aspx for more info)
Cheers!
EDIT
Remember to use #include < Foo.h > as opposed to #include "foo.h". The former searches the include path. The latter uses the local project files.
The additional include directories are relative to the project dir. This is normally the dir where your project file, *.vcproj, is located. I guess that in your case you have to add just "include" to your include and library directories.
If you want to be sure what your project dir is, you can check the value of the $(ProjectDir) macro. To do that go to "C/C++ -> Additional Include Directories", press the "..." button and in the pop-up dialog press "Macros>>".
You mention adding the additional include directory (C/C++|General) and additional lib dependency (Linker|Input), but have you also added the additional library directory (Linker|General)?
Including a sample error message might also help people answer the question since it's not even clear if the error is during compilation or linking.
I am working on a dataManagement project that periodically deletes files in a specific folder. The solution has three projects of which, one is the application and the other two are static libraries. Now I want to add one more project which is a static library used for logging. The logging static library project has a header file which the application project refers. When I build the solution, I am getting error as the header file is not found. When I added the logging static library project, I also made the application project dependent on it by checking the appropriate bix in the project dependencies.
Can anyone please help me?
It needs an additional include file path to reference the header file directory...
Project->Properties->Config Properties->C/C++->Additional Include Directories
it doesn't auto pick up the header file paths, it just knows how to link to the project.... Its completely undefined where the header file should be. or even if you have a header file, you can forward reference the thing in the other project if you like!
There are two things you need to do to get a statically linked library working in VS. The compiler needs to be able to find the declaration for the symbols that you're referencing and the linker needs to be able to resolve the full definition. When you add the .lib file to the VS project this meets the second obligation. To meet the first you must include the header somewhere in your source hierarchy before the first reference and you must also tell the project where to find the header files. The dependency settings in VS only set the build order - they will not help here. You need to make sure that the folder that your header files are in is added to the "Additional Include Directories" setting in the project properties, or is one of the global include directories in the main VS Options. You must also make sure that the .lib is added to the linker's "Additional Dependencies" setting.