Any Unix-like operating system needs a C library: the library which defines the ``system calls‘‘ and other basic facilities such as open, malloc, printf, exit...
The GNU C Library is used as the C library in the GNU systems and most systems with the Linux kernel.
index : http://www.gnu.org/software/libc/
manual: https://www.gnu.org/software/libc/manual/html_node/index.html#toc_Top
download: http://ftp.gnu.org/gnu/glibc/
原文：http://www.cnblogs.com/iclk/p/3929839.html