NFD

# NFD code style guidelines

NFD adopts [NDN Platform C++, C, C#, Java and JavaScript Code Guidelines](http://named-data.net/codebase/platform/documentation/ndn-platform-development-guidelines/cpp-code-guidelines/), with the following exceptions:

* (amended 10). Global variables should have `g_` prefix

* (amended 11). **All** class variables should have `m_` prefix.  Static class variables should have `s_` prefix.

* (amended 31). Thrown exceptions can be either suffixed with ``Exception`` (SecurityException) or ``Error`` (SecurityError).  Alternatively (and it is a recommended method), one should declare exception class ``Exception`` or ``Error`` as an inner class, from which the exception is thrown.  For example, when declaring class Foo that can throw errors, one can write the following:

        #include <stdexcept>

        class Foo

        {

            struct Error : std::runtime_exception

            {

                Error(const std::string& what) : std::runtime_error(what) {}

            };

        };

    In addition to that, if class Foo is a base class or interface for some class hierarchy, then child classes should should define their own ``Error`` or ``Exception`` classes that are inherited from the parent's Error class.

* (amended 33). We will use only `.cpp` and `.hpp` extensions

* (removed 35). Lines should be within a reasonable range. >100 column-lines should be generally avoided.

* (amended 44). Avoid C-style casts.  Use `static_cast`, `dynamic_cast`, `reinterpret_cast`, `const_cast` where appropriate instead.

* (new).  Exceptions can be used in the code, but should be used only in **exceptional** cases and not in the primary processing path.

* (new).  When declaring/defining function/method, the return type should be put on a separate line before function/method name.

* (amended 68).  All three presented styles ARE acceptable.  First and third ARE recommended (these are actually GNU styles).

* (amended 69).  The class declarations should have the following form:

        class SomeClass : public BaseClass 

        { 

        public: 

          ... <public methods> ...

        protected: 

          ... <protected methods> ...

        private: 

          ... <private methods> ...

        public: 

          ... <public data> ...

        protected: 

          ... <protected data> ...

        private: 

          ... <private data> ...

        };

    ``public``, ``protected``, ``private`` may be repeated several times without interleaving (e.g. public, public, public, private, private) if this allows better readability of the code.

* (amended 70) Method and function definitions should have the following form:

        void

        someMethod() 

        { 

          ... 

        }