HP Data Entry and Forms Management System (VPLUS) Reference Manual (32209-90024)
Appendix G 611
TERMINAL INFORMATION
VTURNON/VTURNOFF
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 using VSHOWFORMF.
VTURNOFF can then be called to prepare for graphics operations. A subsequent VTURNON call
will switch the application back to VPLUS 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 applications is to use only VPLUS
procedures to perform terminal input/output operations when in VPLUS. 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 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.
VTURNOFF
Turns off VPLUS block mode and enables character mode access without disturbing the
terminal screen.
Syntax
VTURNOFF {
comarea
}
Parameters
comarea
Must be
comarea
named when the file was opened by VOPENTERM. If not
already set, the following
comarea
items must be set before calling
VTURNOFF.
cstatus
Set to zero.
comarealen
Set to total number of 2-byte words of
comarea
.
VTURNOFF may set the following
comarea
items:
cstatus
Set to nonzero value if call is unsuccessful.
fileerrnum
Set to file error code if there is an MPE file error.
Discussion
VTURNOFF is used for momentarily switching from VPLUS block mode to character mode.
This procedure is designed for use after a terminal has been previously opened by
VOPENTERM or after a VTURNON.