1 Choose a common language

One of the first decisions you need to make when writing portable and cross-platform code is what programming language to use. Ideally, you should choose a language that is widely supported, standardized, and has a rich set of libraries and tools. For example, C and C++ are popular choices for operating system development, as they are low-level enough to access hardware features, but also high-level enough to provide portability and abstraction. However, you should also be aware of the differences and limitations of each language on different platforms, such as data types, endianness, alignment, and calling conventions.

2 Use standards and conventions

Another way to improve the portability and cross-platform compatibility of your code is to follow the standards and conventions of your chosen language and platform. For example, you should use the ISO C and C++ standards, which define the syntax, semantics, and libraries of the languages, and avoid using compiler-specific extensions or features. You should also use the POSIX standard, which defines a common interface for operating system services, such as file systems, processes, signals, and sockets. Additionally, you should follow the coding style and naming conventions of your platform, such as using camelCase or snake_case, or using prefixes or suffixes for types and variables.

3 Use conditional compilation

Conditional compilation is a technique that allows you to include or exclude certain parts of your code based on predefined macros or expressions. This can be useful for writing cross-platform code, as you can use conditional compilation to handle platform-specific differences, such as header files, system calls, data types, or endianness. For example, you can use the #ifdef, #ifndef, #else, and #endif directives in C and C++ to check for the presence or absence of certain macros, such as __linux__, __APPLE__, or __WIN32__, and compile different code blocks accordingly.

4 Use abstraction layers

Abstraction layers are modules or libraries that provide a common interface for different platforms or components, hiding the implementation details and differences behind them. Abstraction layers can help you write cross-platform code, as you can use them to isolate the platform-dependent code from the platform-independent code, and reduce the amount of conditional compilation or duplication. For example, you can use an abstraction layer to wrap the system calls, memory management, or device drivers of different operating systems, and expose a uniform API for your application.

5 Use external libraries

External libraries are precompiled or source code packages that provide functionality or features that are not part of the standard language or platform libraries. External libraries can also help you write cross-platform code, as you can use them to leverage existing solutions or frameworks that are designed to work on multiple platforms, and avoid reinventing the wheel. For example, you can use external libraries to handle tasks such as networking, graphics, user interface, encryption, compression, or testing. However, you should also be careful about the compatibility, licensing, and maintenance of the external libraries you use, and avoid using too many or unnecessary ones.

6 Test and debug

The final step in writing portable and cross-platform code is to test and debug your code on different platforms and environments, and fix any errors or issues that arise. Testing and debugging can help you verify the correctness, performance, and usability of your code, and identify any platform-specific bugs or problems. For example, you can use tools such as compilers, debuggers, profilers, or emulators to test and debug your code on different operating systems, architectures, or devices. You can also use automated testing frameworks, such as unit testing, integration testing, or regression testing, to ensure the quality and consistency of your code across platforms.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?