Directory structure for a C++ library
I am working on a C++ library. Ultimately, I would like to make it publicly available for multiple platforms (Linux and Windows at least), along with some examples and Python bindings. Work is progressing nicely, but at the moment the project is quite messy, built solely in and for Visual C++ and not multi-platform at all.
Therefore, I feel a cleanup is in order. The first thing I'd like to improve is the project's directory structure. I'd like to create a structure that is suitable for the Automake tools to allow easy compilation on multiple platforms, but I've never used these before. Since I'll still be doing (most of the) coding in Visual Studio, I'll need somewhere to keep my Visual Studio project and solution files as well.
I tried to google for terms like "C++ library directory structure", but nothing useful seems to come up. I found some very basic guidelines, but no crystal clear solutions.
While looking at some open source libraries, I came up with the following:
\mylib
\mylib <source files, read somewhere to avoid 'src' directory>
\include? or just mix .cpp and .h
\bin <compiled examples, where to put the sources?>
\python <Python bindings stuff>
\lib <compiled library>
\projects <VC++ project files, .sln goes in project root?>
\include?
README
AUTHORS
...
I have no/little previous experience with multi-platform development/open source projects and am quite amazed that I cannot find any good guidelines on how to structure such a project.
How should one generally structure such a library project? What ca be recommended to read? Are there some good examples?
One thing that's very common among Unix libraries is that they are organized such that:
./ Makefile and configure scripts.
./src General sources
./include Header files that expose the public interface and are to be installed
./lib Library build directory
./bin Tools build directory
./tools Tools sources
./test Test suites that should be run during a `make test`
It somewhat reflects the traditional Unix filesystem under /usr where:
/usr/src Sometimes contains sources for installed programs
/usr/include Default include directory
/usr/lib Standard library install path
/usr/share/projectname Contains files specific to the project.
Of course, these may end up in /usr/local (which is the default install prefix for GNU autoconf), and they may not adhere to this structure at all.
There's no hard-and-fast rule. I personally don't organize things this way. (I avoid using a ./src/ directory at all except for the largest projects, for example. I also don't use autotools, preferring instead CMake.)
My suggestion to you is that you should choose a directory layout that makes sense for you (and your team). Do whatever is most sensible for your chosen development environment, build tools, and source control.
There is this awesome convention that I recently came across that might be helpful: The Pitchfork Layout (also on GitHub).
To sum up, subsection 1.3 states that:
PFL prescribes several directories that should appear at the root of the project tree. Not all of the directories are required, but they have an assigned purpose, and no other directory in the filesystem may assume the role of one of these directories. That is, these directories must be the ones used if their purpose is required. Other directories should not appear at the root. build/: A special directory that should not be considered part of the source of the project. Used for storing ephemeral build results. must not be checked into source control. If using source control, must be ignored using source control ignore-lists. src/: Main compilable source location. Must be present for projects with compiled components that do not use submodules. In the presence of include/, also contains private headers. include/: Directory for public headers. May be present. May be omitted for projects that do not distinguish between private/public headers. May be omitted for projects that use submodules. tests/: Directory for tests. examples/: Directory for samples and examples. external/: Directory for packages/projects to be used by the project, but not edited as part of the project. extras/: Directory containing extra/optional submodules for the project. data/: Directory containing non-source code aspects of the project. This might include graphics and markup files. tools/: Directory containing development utilities, such as build and refactoring scripts docs/: Directory for project documentation. libs/: Directory for main project submodules.
Additionally, I think the extras/ directory is where your Python bindings should go.
I don't think there's actually any good guidelines for this. Most of it is just personal preference. Certain IDE's will determine a basic structure for you, though. Visual Studio, for example, will create a separate bin folder which is divided in a Debug and Release subfolders. In VS, this makes sense when you're compiling your code using different targets. (Debug mode, Release mode.)
As greyfade says, use a layout that makes sense to you. If someone else doesn't like it, they will just have to restructure it themselves. Fortunately, most users will be happy with the structure you've chosen. (Unless it's real messy.)
I find wxWidgets library (open source) to be a good example. They support many different platforms (Win32, Mac OS X, Linux, FreeBSD, Solaris, WinCE...) and compilers (MSVC, GCC, CodeWarrior, Watcom, etc.). You can see the tree layout here:
https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk/
I can realy recommend you using CMake... it's for cross platform development and it's much more flexible that automake, use CMake and you will be able to write cross platform code with your own direcory structure on all systems.
Follow WeChat
Success story sharing
