The charged-particle and energy fluxes to the limiter of a tokamak are calculated and introduced as specific particle and energy sink terms into transport-code calculations. This provides a possibility of obtaining physical boundary conditions in the scrape-off layer. Secondary-electron emission affects, in particular, the electron temperature, the sheath voltage in front of the limiter, and, hence, the energy flux. Results are discussed; within error limits they agree with recent measurements (e.g. on PLT and DITE).