Developer Guides

Navigate to the links below for information on the respective topics:

• The libc code style
  • Naming style
  • Macro style
  • Inline functions and variables defined in header files
  • Setting errno from runtime code
  • Assertions in libc runtime code
  • Allocations in the libc runtime code
  • Warnings in sources
  • Header Inclusion Policy
  • Policy on Assembly sources
  • LIBC_NAMESPACE_DECL
• LLVM-libc Source Tree Layout
  • The benchmarks directory
  • The config directory
  • The cmake directory
  • The docs directory
  • The fuzzing directory
  • The hdr directory
  • The include directory
  • The lib directory
  • The newhdrgen directory
  • The src directory
  • The startup directory
  • The test directory
  • The utils directory
• Entrypoints in LLVM libc
• The libc CMake build system
  • Targets for entrypoints
  • Targets for entrypoint libraries
• Adding new libc configure options
  • Config JSON format
    • Named tags
    • Tag values
    • Option name format
  • Mechanics of config application
    • Config reading
    • Config application
  • Automatic doc update
• LLVM libc clang-tidy checks
  • restrict-system-libc-header
  • implementation-in-namespace
  • callee-namespace
• Fuzzing for LLVM-libc functions
• Types of fuzz tests
• Generating Public and Internal headers
  • Instructions
  • Testing
  • Common Errors
• Convention for implementing entrypoints
  • Implementation Header File Structure
  • .cpp File Structure
• Defining Undefined Behavior
  • Guidelines
  • Approaches
    • Matching Behavior Against Existing Implementations
    • Simplifying Handling Invalid Inputs
    • Conforming to Existing Practice
    • Interpreting the Standard’s Reasoning
    • Ignoring Bug-For-Bug Compatibility
  • Design Decisions
    • Resizable Tables for hsearch
    • Path without Leading Slashs in shm_open
    • Handling of NULL arguments to the ‘s’ format specifier
    • Unknown Math Rounding Direction
    • Non-const Constant Return Values
    • Unrecognized clockid_t values for pthread_rwlock_clock* APIs
    • PThread SpinLock Destroy
• Printf Behavior Under All Conditions
  • Introduction:
    • General Flags:
      • LIBC_COPT_STDIO_USE_SYSTEM_FILE
      • LIBC_COPT_PRINTF_DISABLE_INDEX_MODE
      • LIBC_COPT_PRINTF_INDEX_ARR_LEN
      • LIBC_COPT_PRINTF_DISABLE_WRITE_INT
      • LIBC_COPT_PRINTF_DISABLE_FLOAT
      • LIBC_COPT_PRINTF_DISABLE_FIXED_POINT
      • LIBC_COPT_PRINTF_NO_NULLPTR_CHECKS
      • LIBC_COPT_PRINTF_CONV_ATLAS
      • LIBC_COPT_PRINTF_HEX_LONG_DOUBLE
    • Float Conversion Internal Flags:
      • LIBC_COPT_FLOAT_TO_STR_NO_SPECIALIZE_LD
      • LIBC_COPT_FLOAT_TO_STR_USE_MEGA_LONG_DOUBLE_TABLE
      • LIBC_COPT_FLOAT_TO_STR_USE_DYADIC_FLOAT
      • LIBC_COPT_FLOAT_TO_STR_USE_INT_CALC
      • LIBC_COPT_FLOAT_TO_STR_NO_TABLE
    • Parsing:
    • Conversion