visual c include files from other projects in the same solution

Question

I am working on a game using Visual C    I have some components in separate projects  and have set the project dependencies  How do I  include a header file from a different project  I have no idea how to use classes from one project in another

User · Accepted Answer

Settings for compiler

In the project where you want to #include the header file from another project, you will need to add the path of the header file into the Additional Include Directories section in the project configuration.

To access the project configuration:

Right-click on the project, and select Properties.
Select Configuration Properties->C/C++->General.
Set the path under Additional Include Directories.

How to include

To include the header file, simply write the following in your code:

#include "filename.h"

Note that you don't need to specify the path here, because you include the directory in the Additional Include Directories already, so Visual Studio will know where to look for it.

If you don't want to add every header file location in the project settings, you could just include a directory up to a point, and then #include relative to that point:

// In project settings
Additional Include Directories    ..\..\libroot

// In code
#include "lib1/lib1.h"    // path is relative to libroot
#include "lib2/lib2.h"    // path is relative to libroot

Setting for linker

If using static libraries (i.e. .lib file), you will also need to add the library to the linker input, so that at linkage time the symbols can be linked against (otherwise you'll get an unresolved symbol):

Right-click on the project, and select Properties.
Select Configuration Properties->Linker->Input
Enter the library under Additional Dependencies.

User · Answer

include has nothing to do with projects - it just tells the preprocessor  put the contents of the header file here   If you give it a path that points to the correct location  can be a relative path  like    your file h  it will be included correctly   You will  however  have to learn about libraries  static dynamic libraries  in order to make such projects link properly - but that s another question

User · Answer

Since both projects are under the same solution  there s a simpler way for the include files and linker as described in https   docs microsoft com en-us cpp build adding-references-in-visual-cpp-projects view vs-2019     The include can be written in a relative path  E g   include     libProject libHeader h    For the linker  right click on  References   Click on Add Reference  and choose the other project

User · Answer

Expanding on  Benav s answer  my preferred approach is to    Add the solution directory to your include paths    right click on your project in the Solution Explorer select Properties select All Configurations and All Platforms from the drop-downs select C C     General add   SolutionDir  to the Additional Include Directories  Add references to each project you want to use    right click on your project s References in the Solution Explorer select Add Reference    select the project s  you want to refer to    Now you can include headers from your referenced projects like so    include  OtherProject Header h    Notes    This assumes that your solution file is stored one folder up from each of your projects  which is the default organization when creating projects with Visual Studio  You could now include any file from a path relative to the solution folder  which may not be desirable but for the simplicity of the approach I m ok with this  Step 2 isn t necessary for  includes  but it sets the correct build dependencies  which you probably want

User · Answer

Try to avoid complete path references in the  include directive  whether they are absolute or relative  Instead  add the location of the other project s include folder in your project settings  Use only subfolders in path references when necessary  That way  it is easier to move things around without having to update your code

User · Answer

You need to set the path to the headers in the project properties so the compiler looks there when trying to find the header file s   I can t remember the exact location  but look though the Project properties and you should see it

[c++] visual c++: #include files from other projects in the same solution

Settings for compiler

How to include

Setting for linker

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