The Standard C Library

As we have said, one of the reasons C is a popular language is that it is a "high level" "low level" language. It provides high level programming constructs such as functions, loop, and test which make it easy to write modular, well structured code. At the same time, it provides low level operators and freedom to allow a programer to create their own tools for manipulating their data.

Up until now, we have largely written our own tools when we needed them (e.g. chrutil.h). However, the standard C library provides a large number of built-in utility functions and macros we can use instead of writing our own. The full standard C library is documented in Appendix C of the textbook. The functions provided fall into several categories:

Character Class Tests

String Functions

Utility Functions

including system().

Math Functions

NOTE: to use the math library, you must include <math.h> AND link the math library on the cc line:

               cc whatever.c -o whatever -lm

File I/O Functions

Limit Macros

Others

A full alphabetic listing of the C library is also found in the Appendix.

C library functions are also documented on Unix man pages.

to Overview.