WiringPi is a GPIO access library written in C for the BCM2835 used in the Raspberry Pi. It’s released under the GNU LGPLv3 license and is usable from C and C++ and many other languages with suitable wrappers (See below) It’s designed to be familiar to people who have used the Arduino “wiring” system1
Read more about WiringPI here: http://wiringpi.com/
Down from Here: http://wiringpi.com/download-and-install/
Forum: http://forum.banana-pi.org/t/bpi-wiringpi-is-now-officially-released/268?u=sinovoip