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Code Conventions (C++)

In general the conventions outlined in the Google C++ Style Guide are what we are following. We have some modifications with respect to naming and a few rules to be outlined below.

Naming

Namespaces

In general everything should be in the wn namespace. Furthermore every set of functionality, generally library, should be in it's own sub-namespace. Internal only functionality should be in a further namespace called internal. At the end of every namespace a comment should be included describing the namespace that was closed. Anonymous namespaces should be closed with the comment // namespace to help with identifying start and finish.

namespace wn {
namespace containers {
namespace internal {

class deque_iterator {};

}  // namespace internal

class deque {};

}  // namespace containers
}  // namespace wn

namespace {
}  // namespace

Classes

Class names should be all lower-case with word separation done with underscores. They are already expected to be in a wn::<library>::namespace so the name should not repeat this information.

class my_foo;
struct my_bar;

Functions & Class Methods

Free functions follow the same naming conventions as classes. Their names should be descriptive of the operation they perform, and longer names should be preferred over potentially unclear abbreviations.

Arguments

Function arguments should follow the same rules as functions and methods, but must be prefixed with an _ denoting they are an input/output to/from this method.

int foo(int _bar, int* _baz);

Local Variables

Local variables should be the same as arguments but should omit the underscore.

int foo() {
    int bar = 4;
}

Member Variables

Member variables should be prefixed with m_ so that they can be readily identified.

Static Variables

Private static member variables should be prefixed with s_ in order to identify them. Public static member variables can omit the s_ to conform more with public interface styling. Static variables of any type are generally discouraged, and should only be used with careful thought. Non-member static variables should not be used unless they are constant see Global Constants.

Thread Local Variables

Thread local variables should be prefixed with tl_ in order to identify them. Thread local variables of any type are generally discouraged, and should only be used with careful thought. There should never thread local public members or globals or any kind. If access to one is needed it should be wrapped in some way to disallow direct access.

Global Constants

Global constants should be used in place of Macros wherever possible. They should be named as other variables, but prefixed with k_ in order to identify hem.

Template Parameters

Template parameters should be in sentence case. One exception is if the usage is very localized and clear, an abbreviated form can be used.

template <typename MyType>
class fooClass {
  ...
};

template <typename T>
operator=(const T& _other) {
  ...
}

Include Guards

Include guards follow the same structure as the namespace and class name for the main class in the file. This should also be the file name. The closing of the include guard should also contain a comment describing what has been closed. Also, always use both include guards and #pragma once to ensure fastest compilation.

#pragma once
#ifdef __WN_CONTAINERS_DEQUE_H__
#define __WN_CONTAINERS_DEQUE_H__

...

#endif  // __WN_CONTAINERS_DEQUE_H__

Macros

Macros should be avoided if possible, but sometimes it is required. Other than include guards preprocessor directives should be ALL_CAPS separated by _ characters. In conditional preprocessor sections, at the end of the directive a comment should be included describing the section that was closed.

#define MY_FOO
#define MY_FOO(bar)
#ifdef FOO

...

#endif  // FOO

Numeric Types

As a rule, the numeric types specified in <cstdint> should be used instead of the more traditional int and long int types. This ensures clarity of width, and more control over data types than otherwise.

Discarding Return Values

Returns from function should always try to be incorporated into proper program flow, but in the rare cases where ignoring the return explicitly is desired the use of a C-style void cast should be used. This is the only place that a C-style cast should be used in C++ code.

int foo() {
  return 1;
}

(void)foo(); // this is ok
static_cast<void>(foo()) // this is discourage

System Specific Code

When writing system-specific code, Win32 for example, any variables, functions that interact with system-specific API should use the types expected by the API documentation, rather than their equivalent types from this document. Also, when able, prefix all system-specific code with :: to help in avoiding name collisions.

::GetModuleHandle(NULL); // this is OK
::GetModuleHandle(nullptr); // this is discouraged
GetModuleHandle(NULL); // add global namespace ::

Formatting

Our formatting is based off the Google C++ style guide with some modifications. We use clang-format extensively, and it should handle all formatting. We support clang-format version 10. See our .clang-format for further details.