Libraries and header files

The standard libraries supplied by the C compilation system contain functions that you can use in your program to perform input/output, string handling, and other high-level operations that are not explicitly provided by the C language. Header files contain definitions and declarations that your program will need if it calls a library function. They also contain function-like macros that you can use in your program as you would a function.

The first section of this chapter shows you how to link your program with these standard libraries and how to include a header file. This section illustrates the use of header files and library functions in your program. It also describes the contents and location of some of the more important standard libraries (libc, libm, and libgen), along with a brief discussion of standard I/O.