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

Chapter 6 235
USING VPLUS INTRINSICS
COMMUNICATION AREA
COMMUNICATION AREA
Every application that calls VPLUS intrinsics must allocate a data area in the application
for communication with the intrinsics. This area (called the
comarea ) is the first, and often
the only, parameter in every call to a VPLUS intrinsic. Table 6-4. briefly outlines the
contents of this communication area; Table 6-5. outlines the items used for data capture
devices. It is essential to successful operation of your application that the
comarea be
defined exactly as shown in these tables; items that are "Reserved for system use" should
not be set or used after they are initialized. The
comarea items listed in Table 6-4. and are
defined below.
Table 6-4. Outline of Communication Area Contents
Data Type Position Offset Name Function
Integer
(Two-byte)
10 cstatus status, error returns
21 language programming language of calling program
32 comarealen length of comarea length of comarea in
two-byte words
43 usrbuflen comarea extension length (BASIC)
54 cmode current mode (collect or browse)
65 lastkey code of last key pressed
76 numerrs number of errors in current form
87 windowenh code for window enhancement
98 multiusage Child of previous form
10 9 labeloption function key label indicator
Character
Array
(16-byte)
11-18 10-17 cfname current form name (15 characters)
19-26 18-25 nfname next form name (15 characters)
Integer
(Two-byte)
27 26 repeatapp current form flag (repeat/append)
28 27 freezapp next form flag (freeze/append)
29 28 cfnumlines number of lines in current form
30 29 dbuflen data buffer length (in bytes)
Integer
(Two-byte)
31 30 Reserved for
system use.
—
Logical
(Two-byte)
32 31 lookahead flag for background form load in
VREADFIELDS
33 32 deleteflag delete current batch record