Sure, if you simply do full-text search for that expression over whole nRF5 SDK package (typically filtered on C and H files) you will see where it is used. Because your question suggests that you have little idea about writing C code on embedded system let me warn you: this is useful only if you are writing some kind of test firmware or your own radio stack. If you intend to use some existing technology such as BLE then you never manage such low-level things from your application, this is job of lower stack.
Sure, if you simply do full-text search for that expression over whole nRF5 SDK package (typically filtered on C and H files) you will see where it is used. Because your question suggests that you have little idea about writing C code on embedded system let me warn you: this is useful only if you are writing some kind of test firmware or your own radio stack. If you intend to use some existing technology such as BLE then you never manage such low-level things from your application, this is job of lower stack.
