HP 3000 Manuals HP 3000 Manuals
VTURNON/VTURNOFF VOPENTERM configures the driver and the terminal for block mode access. VCLOSETERM configures the terminal and driver for character mode access. These procedures initialize the terminal in many ways, including clearing the screen image. VTURNON and VTURNOFF reconfigure the terminal and driver but leave the terminal screen image intact. VTURNOFF allows the application to switch momentarily to character mode from block mode without disturbing the screen. A call to VTURNON will reconfigure the terminal back to block mode. An example of such use is an application which performs graphics input/output after the terminal has been opened by VOPENTERM and a form has been displayed. VTURNOFF can then be called to prepare for graphics operations. A subsequent VTURNON call will switch the application back to VPLUS/V block mode. The use of VOPENTERM, VCLOSETERM, VTURNON and VTURNOFF provides for a systematic approach to controlling the terminal and driver settings. The recommended practice for programming VPLUS/V applications is to use only VPLUS/V procedures to perform terminal input/output operations when in VPLUS/V. If the application must perform terminal input/output operations using other input/output methods, either VCLOSETERM or VTURNOFF must be used to switch out of VPLUS/V before doing so. This simple programming guideline assures that the application will be compatible with the different HP3000 drivers and terminals, and improves its maintainability.