Platform-Specific Features in C++

C++ is a great general-purpose language. Thanks to the Standard Library, the language is packed with so many features that a casual programmer could happily code in C++ for years without going beyond what is built in. However, professional programs require facilities that C++ does not provide. This section lists several important features that are provided by the platform or third-party libraries, not by the C++ language or the C++ Standard Library:

Networking

The Internet has changed the way we write applications. These days, most applications check for updates through the web, and games provide a networked multiplayer mode. C++ does not provide a mechanism for networking yet, though several standard libraries exist. The most common means of writing networking software is through an abstraction called sockets. A socket library implementation can be found on most platforms, and it provides a simple procedure-oriented way to transfer data over a network. Some platforms support a stream-based networking system that operates like I/O streams in C++. There are also third-party networking libraries available that provide a networking abstraction layer. These libraries often support many different target platforms. Choosing a networking library that is IPv-independent would be a better choice than choosing one that only supports IPv4, as IPv6 is already being used.

Graphical user interfaces

Most commercial programs today run on an operating system that has a graphical user interface, containing such elements as clickable buttons, movable windows, and hierarchical menus. C++, like the C language, has no notion of these elements. To write a graphical application in C++, you can use platform-specific libraries that allow you to draw windows, accept input through the mouse, and perform other graphical tasks. A better option is to use a third-party library, such as wxWidgets (https://wxwidgets.org), Qt (qt.io), Uno (platform.uno), and many more that provide an abstraction layer for building graphical applications. These libraries often provide support for many different target platforms.

OS events and application interaction

In pure C++ code, there is little interaction with the surrounding operating system and other applications. The command-line arguments are about all you get in a standard C++ program without platform extensions. For example, operations such as copy and paste (which interact with the operating system's clipboard) are not directly supported in C++. You can either use platform-provided libraries or use third-party libraries that support multiple platforms. For example, both wxWidgets and Qt are examples of libraries that abstract the clipboard operations and support multiple platforms.

Low-level files

Many operating systems provide their own file APIs, which are usually incompatible with the standard file classes in C++. These libraries often provide OS-specific file tools, such as a mechanism to get the home directory of the current user.

Threads

Concurrent threads of execution within a single program were not directly supported in C++03 or earlier. Since C++11, a threading support library has been included with the Standard Library and C++17 has added parallel algorithms. If you need more powerful threading functionality besides what the Standard Library provides, then you need to use third-party libraries.

Note: If you are doing cross-platform development and you need functionality not provided by the C++ language or the C++ Standard Library, you should try to find a third-party cross-platform library that provides the functionality you require. If, instead, you start using platform-specific APIs directly, then you are complicating your cross-platform code a lot, as you will have to implement the functionality for each platform you need to support.

Note: When using third-party libraries, if possible, get these libraries as source code and build them yourself with the exact toolchains you need.