You can find the binaries of gcc over /usr/bin/gcc and the libraries over /usr/lib/gcc. If you want to check what you currently have installed use opkg list-installed . Regarding opencv, make sure you also have all the required packages prior to the installation. You can find the dependencies listed in here http://docs.opencv.org/doc/tutorials/introduction/linux_install/linux_install.html. I hope you find this helpful.