Using the SDK to cross compile

Cross compiling with the help of the SDK is not much different from normal compilation. There are some more pitfalls, but let’s get on with the happy cases for now.

Sourcing The Environment

After the installation the SDK it needs to be sourced. This means that the SDK toolchain and the sysroot environment variables will be set in your active terminal session.

cd ~/sdk
source environment-setup-<arch>-poky-linux

To check if the environment has already been sourced grep for variables which start with OECORE in the environment for example like this:

env | grep OECORE

This means that the environment has been sourced.

Cross Compiling

In the easiest case, when all the projects dependencies are already installed in the SDK, cross-compiling is really easy. Navigate in to the directory and use cmake and make to compile it as you normally would. The environment will make sure that the right compiler and cmake will be used.

In the case of additional external dependencies, it’s recommended to install them into the SDK so that they can be found by tools like pkg-config. The cmake tool provided with the SDK does that by default, so when building a shared library using cmake one would typically issue these commands:

mkdir build && cd build
cmake ..
make install  # prefix with sudo, if the SDK sysroot is not user-writable

and the library would be immediately usable by all applications building on the SDK.