Cstyle

Cstyle refers to the conventional approach to writing C code that is followed by programmers to produce readable, maintainable, and portable software. It is not a single universal standard; rather it is a collection of guidelines developed by individual projects, communities, or institutions. Cstyle typically covers formatting, naming, and organizational practices that aim to improve consistency across a codebase.

Common elements include indentation style (tabs or spaces), brace placement (K&R, Allman, or other variants), line length limits, and naming conventions for types, variables, and functions. They may prescribe header file organization with include guards, the ordering of includes, and disciplined use of macros. Additional rules address typedef usage, pointer declarations, const correctness, and the separation of interface and implementation.

Historically, C style emerges from early C community practices and has evolved alongside the ANSI C standard (C89/C90) and later standards such as C99 and C11. In practice, large projects—especially operating system kernels, standard libraries, and embedded systems—maintain their own Cstyle guides. Notable examples include the Linux kernel coding style and the GNU coding standards, which influence many open-source projects.

As there is no universal enforcement, Cstyle is project-specific and can differ between teams. Tools such as automated formatters and static analysis can help enforce rules, but teams must balance strictness with readability and pragmatics. Critics warn that rigid rules may hinder clarity or innovation, while proponents argue that a shared style reduces cognitive load during code review and collaboration.