CMake Style Guidelines

General Formatting

• Indentation: Use 2 spaces for indentation. Avoid tabs to ensure consistency across different environments.

• Line Length: Limit line length to 100 characters where possible.

• Empty Lines: Use empty lines to separate logically distinct sections within a CMake file.

• No Space Before Opening Brackets: Do not add a space between a command and the opening parenthesis. Use if(...) instead of if (...).

  # Good:
  if(ENABLE_TESTS)
    add_subdirectory(tests)
  endif()
  
  # Bad:
  if (ENABLE_TESTS)
    add_subdirectory(tests)
  endif()
  

Commands and Syntax

• Lowercase Commands: Always use lowercase CMake commands (e.g., add_executable, find_package). This improves readability and consistency.

  # Good:
  add_library(my_lib STATIC src/my_lib.cpp)
  
  # Bad:
  ADD_LIBRARY(my_lib STATIC src/my_lib.cpp)
  

• One File Argument per Line: Break the file arguments across multiple lines to make it easier to scan and identify each source file or item.

  # Good:
  target_sources(my_target PRIVATE
    src/file1.cpp
    src/file2.cpp
  )
  
   # Bad:
  target_sources(my_target PRIVATE src/file1.cpp src/file2.cpp)
  

Variable Naming

• Use Uppercase for Cache Variables or variables shared across CMake files: When defining cache variables using option or set(... CACHE ...), use UPPERCASE names.

  option(ENABLE_TESTS "Enable test suite" ON)
  set(CMAKE_CXX_STANDARD 17 CACHE STRING "C++ standard version")
  

• Use Lowercase for Local Variables: For local variables within CMake files, use lowercase or snake_case.

  set(output_dir "${CMAKE_BINARY_DIR}/output")
  

• Consistent Prefixing: Use consistent prefixes for variables to avoid name conflicts, especially in large projects.

  set(MYPROJECT_SRC_DIR "${CMAKE_SOURCE_DIR}/src")
  

Quoting

• Quote Strings and Variables: Always quote string literals and variables to prevent unintended behavior, especially when dealing with paths or arguments that may contain spaces.

  # Good:
  set(my_path "${CMAKE_SOURCE_DIR}/include")
  
  # Bad:
  set(my_path ${CMAKE_SOURCE_DIR}/include)
  

• Do Not Quote Boolean Values: For boolean values (ON, OFF, TRUE, FALSE), avoid quoting them.

  option(BUILD_SHARED_LIBS "Build shared libraries" OFF)
  

Avoid Hardcoding Paths

• Use CMake variables (CMAKE_SOURCE_DIR, CMAKE_BINARY_DIR, CMAKE_CURRENT_SOURCE_DIR) instead of hardcoding paths.

  set(output_dir "${CMAKE_BINARY_DIR}/bin")
  

Conditional Logic

• Use if, elseif, and else with proper indentation, and close with endif().

  if(ENABLE_TESTS)
    add_subdirectory(tests)
  endif()
  

Documentation

• Use comments to document complex logic in the CMake files.

  # Find LlvmLld components required for building with llvm
  find_package(LlvmLld 14.0.0 REQUIRED)