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