HP 3000 Manuals HP 3000 Manuals
ADVANCED TERMINAL I/O PROCEDURES In general, the VPLUS/V terminal input/output procedures such as VOPENTERM, VCLOSETERM, VREADFIELDS and VSHOWFORM are sufficient for most applications that communicate with a user via a terminal interface. In building complex user interfaces, however, application designers have a limited number of tools for implementation. Hence, they resort to using FREAD, FWRITE, and input/output verbs of their programming language to display and retrieve information from the terminal when running VPLUS/V. The situation becomes more complicated when the application controls the terminal settings as well as the driver settings, and is likely to result in an application that runs in a restricted environment; for example, on an ATP an on one kind of terminal only. VPLUS/V provides two additional procedures that help application designers to write applications with complex user interfaces that are more portable and easier to maintain. They are VTURNON and VTURNOFF.