Hi, i wanted know what serve the libraries in arduino?
thank you for reply...
Not sure what you want.
For each version IDE there are libraries to match that come with the IDE. You can add any of those using IDE Sketch->Import Library. You can add others to the libraries folder as well.
Here is the library modules reference at AVR LibC:
http://www.nongnu.org/avr-libc/user-manual/modules.html
totonno87:
Hi, i wanted know what serve the libraries in arduino?
thank you for reply...
What is you real question ? 
Do you mean servo libraries>?
New libraries that you want to add should be placed in a libraries subfolder in the sketchbook folder.