headerfirst

headerfirst is a term that refers to a software development practice where the header file for a particular module or class is included at the very beginning of the source code file. This approach is often contrasted with including header files later in the source file, sometimes after other code or even other header files.

The primary motivation behind the headerfirst practice is to improve build times. When a header file is included first, the compiler processes it before encountering any other code that might depend on it. This can allow for more efficient parsing and analysis of the header file, especially in complex projects with deep include hierarchies. Some build systems and compilers are optimized to handle this structure more effectively.

Additionally, adopting headerfirst can encourage developers to organize their code more logically. It forces a clear separation between interface definitions (in headers) and implementation details (in source files). This can lead to more maintainable and understandable codebases, as the dependencies and structure of a module are immediately apparent at the top of the file.

However, headerfirst is not universally adopted. Some developers prefer to include headers closer to where they are first used, believing it can make dependencies more explicit within the flow of the code. The choice between headerfirst and other inclusion strategies often depends on project conventions, team preferences, and the specific build tools and compilers being used. The effectiveness of headerfirst can also vary depending on the programming language and the complexity of the project.