C includes a variety of utility libraries. These libraries can be broadly divided into two groups:
- language support libraries, and
- general-purpose libraries.
 Language support
Language support libraries provide functions that interact closely with language features and support common language idioms.
Assertions (e.g. assert)
Support for functions that take an arbitrary number of parameters (via e.g. va_start, va_arg, va_end)
 General-purpose utilities
 See also
C++ documentation for Utility library