This manual is written with the assumption that you are at least
somewhat familiar with the C programming language and basic programming
concepts. Specifically, familiarity with ISO standard C
(see ISO C), rather than “traditional” pre-ISO C dialects, is
The GNU C library includes several header files, each of which
provides definitions and declarations for a group of related facilities;
this information is used by the C compiler when processing your program.
For example, the header file stdio.h declares facilities for
performing input and output, and the header file string.h
declares string processing utilities. The organization of this manual
generally follows the same division as the header files.
If you are reading this manual for the first time, you should read all
of the introductory material and skim the remaining chapters. There are
a lot of functions in the GNU C library and it's not realistic to
expect that you will be able to remember exactly how to use each
and every one of them. It's more important to become generally familiar
with the kinds of facilities that the library provides, so that when you
are writing your programs you can recognize when to make use of
library functions, and where in this manual you can find more
specific information about them.
Published under the terms of the GNU General Public License