Good observation! The shift is intentional - safety-critical code typically doesn't "output" in the printf sense. Instead it returns status codes and modifies state that the caller inspects.
The pulse monitor example returns PULSE_OK/PULSE_ERR_* codes, and the caller queries state via pulse_status(). In a real system, that status feeds into a larger state machine or triggers hardware responses - not console output.
That said, the c-from-scratch repo (https://github.com/SpeyTech/c-from-scratch) does include demo programs with actual output for learning purposes.
The article focuses on the methodology shift rather than a complete runnable example.
Fair point though - I could add a note about where to find working demos.