A few years ago, every Linux system used the libc version 5.x library. The libc library is the main library that all Unix C programs use.The functions they access are defined in that library.Recently a new version of the library was introduced by the GNU project called GNU libc, or glibc, which is also called libc 6. Some distributions and older systems won't have glibc, and they won't support glibc binaries.
This doesn't change anything for binaries you compile, but binaries you download that are linked to the GNU libc will not work.There are 2 ways to get them to work. The first is to upgrade. You can upgrade to a newer version that does support glibc, or change your distribution to one that already has glibc as its main library. The
other way is to install glibc on your current system.
This requires you to know what you are doing and to backup your system first. See the GNU page at http://www.gnu.org page for more information on GNU products.
"Windows Linux Tips: Libc versus Glibc"
Reference : techpraveen.com