roslib

Base dependencies and support libraries for ROS. roslib contains many of the common data structures and tools that are shared across ROS client library implementations.

Homepage: http://wiki.ros.org/roslib

roslib is the base library support for ROS client implementations as well as ROS tools. It includes:

common message definitions used in ROS clients (e.g. Header)
a Python library for manipulating ROS system resources (e.g. .msg files, names)
message and services generation callout scripts

Code API

Time-related: ros::Time, ros::Duration, ros::Rate, ros::WallTime, ros::WallDuration, ros::WallRate. Also see the roscpp Time overview.
Package-related: ros::package namespace
Debug-related: ros::debug namespace