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.

VTURNOFF reconfigures the terminal and driver for character mode operations without disturbing the screen image on the terminal. The following operations normally performed in VCLOSETERM are not performed in VTURNOFF:

• Clear local form storage

• Enable the USER/SYSTEM keys

• Disable touch reporting, delete touch fields

• Clear screen

• Unlock keyboard

• Close terminal file

VTURNOFF

	NOTE: VTURNOFF does not close the terminal file. To close the field and completely reset the driver and the terminal, VCLOSETERM must be used.

Example

The following examples illustrate a call to VTURNOFF: COBOL CALL "VTURNOFF" USING COMAREA. BASIC 200 CALL VTURNOFF (C(*)) FORTRAN CALL VTURNOFF (COMAREA) SPL VTURNOFF (COMAREA); PASCAL VTURNOFF (COMAREA);

VTURNON

Turns on VPLUS block mode without disturbing the terminal screen.

Syntax

VTURNON {comarea,TERMFILE}

Parameters

comarea

The comarea name must be unique for each open forms file. The comarea must be the same one used in VOPENTERM. The following comarea items must be set before the call if not already set:

cstatus

Set to zero.

language

Set too code that identifies the programming language of the calling program.

comarealen

Set to total number of 2-byte words in comarea.

VTURNON may set the following comarea fields.

cstatus

Set to nonzero value if call is unsuccessful.

fileerrnum

Set to file error code if there is an MPE file error.

filen

Set to MPE file number of terminal.

identifier

Set to appropriate VPLUS terminal ID.

lab'info

Set to appropriate number and length of labels.

Discussion

VTURNON is normally used in an application when the terminal has already been opened by VOPENTERM and VTURNOFF was called to switch out of VPLUS block mode. VTURNON switches the application back to VPLUS block mode without disturbing the image on the terminal screen.

After a VTURNON, you must perform a VSHOWFORM. You must also unlock your keyboard. Sending the escape sequence ESC-b unlocks the keyboard programmatically, or depressing the RESET key once also unlocks the keyboard.

VTURNON reconfigures the terminal and the driver without performing the following operations, which are usually carried out by VOPENTERM.

• Initialize local form storage

• Clear screen

• Enable the USERKEYS function keys

• Disable or enable the USER/SYSTEM key as specified in the SHOWCONTROL word

Unlike VOPENTERM, VTURNON will not ask you to press the BLOCK MODE key if you are using an HP2640B or HP2644 terminal and the terminal is not on block mode.

Example

The following examples illustrate a call to VTURNON: