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rcutils: ROS 2 C Utilities data structures

rcutils is a C API consisting of macros, functions, and data structures used through out the ROS 2 code base.

Quality Declaration

This package claims to be in the Quality Level 1 category, see the Quality Declaration for more details.


The API is a combination of parts:

  • Allocator concept, used to inject the allocating and deallocating methods into a function or type.
    • rcutils_allocator_t
    • rcutils/allocator.h
  • Command line interface utilities:
    • rcutils/cmdline_parser.h
  • Utilities for setting error states (error message, file, and line number) like strerror for errno:
    • rcutils/error_handling.h
  • Some basic filesystem utilities like checking for path existence, getting the cwd, etc...:
    • rcutils/filesystem.h
  • A C string find method:
    • rcutils_find()
    • rcutils_find_last()
    • rcutils/find.h
  • A convenient string formatting function, which takes a custom allocator:
    • rcutils_format_string()
    • rcutils/format_string.h
  • Functions for interfacing with process environment variables:
    • rcutils_get_env()
    • rcutils_get_home_dir()
    • rcutils_set_env()
    • rcutils/env.h
    • rcutils/get_env.h
  • Extensible logging macros:
    • Some examples (not exhaustive):
    • rcutils/logging_macros.h
    • rcutils/logging.h
  • Some basic utilities to load, unload and get symbols from shared libraries at run-time.
    • rcutils/shared_library.h
  • A string replacement function which takes an allocator, based on
    • rcutils_repl_str()
    • rcutils/repl_str.h
  • String splitting functions which take a custom allocator:
    • rcutils_split()
    • rcutils_split_last()
    • rcutils/split.h
  • A version of strdup which takes an allocator:
    • rcutils_strdup()
    • rcutils/strdup.h
  • Portable implementations of "get system time" and "get steady time":
    • rcutils_system_time_now()
    • rcutils_steady_time_now()
    • rcutils/time.h
  • Some useful data structures:
    • A "string array" data structure (analogous to std::vector<std::string>):
      • rcutils_string_array_t
      • rcutils/types/string_array.h
    • A "string-string map" data structure (analogous to std::map<std::string, std::string>)
      • rcutils_string_map_t
      • rcutils/types/string_map.h
  • Macros for controlling symbol visibility and linkage for this library:
    • rcutils/visibility_control.h