C Coding Standards

When reviewing or generating C code, follow these rules:

File Naming

• Source files: snake_case with .c extension (e.g., user_service.c , data_parser.c )

• Header files: snake_case with .h extension (e.g., user_service.h , data_parser.h )

• Keep names short but descriptive (max ~20 characters)

Header Guards

• Format: UPPER_SNAKE_CASE with _H suffix

• Include path in guard: (e.g., PROJECT_MODULE_FILE_H )

#ifndef USER_SERVICE_H #define USER_SERVICE_H // content #endif /* USER_SERVICE_H */

Variable Naming

• Local variables: snake_case (e.g., user_count , buffer_size , is_valid )

• Global variables: snake_case with g_ prefix (e.g., g_config , g_instance_count )

• Static variables: snake_case with s_ prefix (e.g., s_initialized , s_cache )

• Pointers: Include p or ptr suffix when helpful (e.g., user_ptr , buffer_p )

Constant/Macro Naming

• Macros: UPPER_SNAKE_CASE (e.g., MAX_BUFFER_SIZE , DEFAULT_TIMEOUT )

• Enum values: UPPER_SNAKE_CASE (e.g., STATUS_OK , ERROR_INVALID_INPUT )

• Compile-time constants: UPPER_SNAKE_CASE with #define

Function Naming

• Functions: snake_case (e.g., calculate_total() , parse_input() )

• Module prefix: Use module name prefix (e.g., user_create() , user_destroy() )

• Static functions: snake_case, no prefix needed (internal to file)

• Init/cleanup pairs: Use _init() and _cleanup() or _create() and _destroy()

Type Naming

• Structs: snake_case with _t suffix or PascalCase (e.g., user_data_t or UserData )

• Typedefs: snake_case with _t suffix (e.g., user_id_t , callback_fn_t )

• Enums: snake_case with _e suffix for type (e.g., status_e )

Organization

• Header includes at top (system headers, then project headers)

• Macro definitions after includes

• Type definitions (structs, enums, typedefs)

• Function prototypes

• Global/static variable declarations

• Function implementations