README

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.

API

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_LOG_DEBUG()

      • RCUTILS_LOG_INFO_NAMED()

      • RCUTILS_LOG_WARN_ONCE()

      • RCUTILS_LOG_ERROR_SKIPFIRST_NAMED()

    • 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 http://creativeandcritical.net/str-replace-c:

    • 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