What is a good project structure in C

Question

Hi, I have been working in Java/J2ee projects, in which I follow the Maven structure. I want to develop [say a command line interpreter in linux {ubuntu}] in C. I never develop projects in C. I want to know what project structure I should follow.

Answer 1

There is no one "standard" for C project in this aspect. Certainly if your project is small, then frequently everything will be placed in a single directory.

You can try to download some popular open-source C projects and take a look at their code.

On a lower level, code should be modular. Each module (which in C is usually manifested in a data structure with a set of functions to act upon it) has its own pair of .h and .c files, with the .h file being the public interface visible to the clients of the module, and the .c file being the private implementation.

Answer 2

You can refer to the OpenSSL Project structure. It's a famous open source and has a good project structure.

Answer 3

Separate functionalities in modules: .c files with implementation details/definitions paired with .h files with declarations.

Try not to pollute namespaces by using static for functions and a common module prefix for external symbols.

Create libraries if you have functionalities that can be encapsulated and reused.

Answer 4

A suggestion:

/project
    README
    LICENCE
    Makefile 
    # mabe configure.am Makefile.am etc. 
    # see http://en.wikipedia.org/wiki/GNU_build_system
    /src
        Makefile
        a.h
        a.c
        b.h
        b.c 
        /subunit
            x.h
            x.c
            y.h
            y.c
        # each file.c has a header file.h but not necessarily
        ...

Look at Nginx on github and browse the project structure online.

Answer 5

As Eli Bendersky sayd, it strictly depends on how complex is your project.

The standard suggests to split as much as possible into libraries. The point is that you may want to reuse your libraries elsewhere. By example this is a project of mine:

├── AUTHORS
├── COPYING
├── ChangeLog
├── Makefile.am
├── NEWS
├── README
├── configure.ac
├── libs
│   ├── featsel
│   │   ├── Makefile.am
│   │   ├── commander.c
│   │   ├── featsel
│   │   │   ├── commander.h
│   │   │   ├── feattuple.h
│   │   │   └── types.h
│   │   ├── featsel.h
│   │   ├── feattuple.c
│   │   ├── headers
│   │   │   └── datatypes.h
│   │   └── tests
│   │       ├── Makefile.am
│   │       └── test00.c
│   ├── mbox
│   │   ├── Makefile.am
│   │   ├── README
│   │   ├── control.c
│   │   ├── error.c
│   │   ├── headers
│   │   │   ├── datatypes.h
│   │   │   ├── mail.h
│   │   │   ├── parse.h
│   │   │   ├── split.h
│   │   │   └── strings.h
│   │   ├── interface.c
│   │   ├── mail.c
│   │   ├── mbox
│   │   │   ├── descriptor.h
│   │   │   ├── error.h
│   │   │   ├── mail.h
│   │   │   └── types.h
│   │   ├── mbox.h
│   │   ├── parse.c
│   │   ├── split.c
│   │   └── strings.c
│   └── thread_queue
│       ├── Makefile.am
│       ├── thrdqueue.c
│       └── thrdqueue.h
├── reconf
└── src
    ├── Makefile.am
    └── main.c

I personally prefer to put all libraries into a libs directory. Every library except trivial ones has its own private header directory and exports a public header by means of a directory having the same name of the library.

The source file of the program itself is placed in the src directory.