Libraries are often used to reuse a specific functionality across various application binaries. Gnu compiler collections are shipped with glibc as a standard library to provide functions that are generally used in C source programs. Application developers may use other 3rd party libraries to link a specific functionality as per the application need. For example and audio player application written in C could use standard C library functions linked from glibc and also use ready functions to process audio data linking a specific library like libmp3. we will look at how shared libraries are created and how applications can link with them.