How do I add semihosting to an existing project?
Normally you would select whether a project will make use of semihosting by using the appropriate project wizard when the project is first created:
However sometime it can be useful to convert an existing project so that it makes use of semihosting. To do this you need to change the selected library variant being used when the project is built - typically from 'none' to 'semihost'. Details of how to do this can be found in the FAQ Switching the selected C library