HP Data Entry and Forms Management System (VPLUS) Reference Manual (32209-90024)

Appendix L 653
A Programmer’s Guide to VPLUS
VPLUS Intrinsic Calls
COMAREA words have been set from preceding VPLUS intrinsic calls. If CSTATUS word of the
user’s COMAREA is not zero, the call to VPUTBUFFER does not execute. The buffer is the name
of the program’s form buffer whose contents are to be put to the form. The third parameter
is the length of the buffer in bytes.
VSHOWFORM
Purpose: to display screen definition, data, window function keys, enhancements or
terminal screen.
This intrinsic takes the current form as defined in the comarea extension form definition
and displays it on the screen. A prior call to VGETNEXTFORM places the form definition in the
comarea extension. VSHOWFORM displays the field values from the data buffer of the
comarea extension. The content of the data buffer is affected by calls to VINITFORM,
VPUTBUFFER or VREADFIELDS. VSHOWFORM also uses the global/form function keys and
window buffer from the comarea extension to display the softkey labels and the window
message.
The only parameter which is passed to VSHOWFORM is COMAREA. The SHOWCONTROL word in
the COMAREA allows the programmer control of several VSHOWFORM options. The following
paragraphs discuss some of the options and how they are used.
Bit 15=1 Forces the form to be displayed again.
This overrides the VPLUS default. This may be useful when using process
handling and returning to the father process’ screen. In some cases,
VPLUS does not show the father process screen when control is returned
to the father process because it believes the father screen is the current
form. Bit 15 must be set to 1 in this case.
Bit 14=1 Forces the window to be displayed again.
The other intrinsics which force the window to be displayed again are
VPUTWINDOW, VSETERROR, VGETNEXTFORM with NFNAME=$REFRESH.
Bit 13=1 Forces the data to be displayed again.
VPLUS normally does not re-display values that are already on the screen.
Setting bit 13 to 1 overrides the default, and may be used as another
alternative to $REFRESH. In most cases, forcing the data to be displayed
again is sufficient rather than using $REFRESH which will re-display data,
screen design, window and softkeys. (Refer to the example of how this is
performed in the preceding VGETNEXTFORM discussion).
Bit 10=0 Enables the keyboard (default).
Bit 10=1 Disables the keyboard.VREADFIELDS locks the keyboard so that no user
input can take place until the screen is displayed. VSHOWFORM unlocks the
keyboard so that a user may enter data after the screen is displayed. If
more than one VSHOWFORM is called in a row without an intervening call to
VREADFIELDS, bit 10 should be set to 1. After the last VSHOWFORM is
called, bit 10 should be set back to 0 to allow user input of data.
Bit 9=0 Do not preload current form into local form storage (default).
Bit 9=1 Preload form into local form storage.