Calls to some library routines and dynamic link libraries (DLLs) may have some unique characteristics in thin client environments, as opposed to distributed processing deployments. Implementations of the C$COPY, C$SYSTEM, and W$KEYBUF library routines, among others, are included in this category. The method for calling DLLs on the display host as well as on a Windows application host (server) is also somewhat different for thin client deployments.