The files in here are used in the execution of examples and tests.
The core of runner is the macro U_RUNNER_FUNCTION. This macro wraps every example and every test in ubxlib and takes advantage of a C++ feature in compilers, namely the constructor attribute. The constructor attribute identifies a function as one that must be run during C startup, before entry into main(). The U_RUNNER_FUNCTION macro creates a unique function name for the function it is wrapping and, during C startup, calls a registration function which puts that unique function name into a linked list which is fully populated by the time code starts to run for real.
The other runner functions allow the functions in the linked list to be executed, printed, sorted, etc.
By this means all the ubxlib examples and tests can be compiled at the same time, loaded into the list, executed and checked for correctness, without collisions of definitions of main() or the need for a separate set of build metadata for each example/test/platform/SDK combination.