VPLUS makes use of the DL area for buffers and internal tables.
Therefore, if the DL area is put to any other use during the execution
of a VPLUS application, such use must not conflict with that of
VPLUS. To insure against conflict, observe the following rules:
The first use of the DL area by an application, including
any procedures, routines, or intrinsics executed on behalf of the
application, should be the call to VOPENFORMF that opens the forms file and allocates the DL
area needed by VPLUS.
The call to VCLOSEFORMF that frees up the DL area used by VPLUS must not
occur until the application has released all other DL space allocated
subsequent to the VOPENFORMF call.
These restrictions need not be followed if the application
is wholly coded in any combination of Pascal, HPFORTRAN 77, and
HPBUSINESS BASIC and sets the comarea item language to
5, which causes VPLUS to use the heap procedures provided by Pascal instead
of managing the DL area directly.
VPLUS applications coded in other languages need to take great
care if they pass the language identifier of 5 as a means of getting around the
restrictions stated above. Specifying an incorrect language identifier
can cause other aspects of the VPLUS interface, such as addressing
of byte parameters, to function unreliably. In such a case, the application
must use the INTRINSIC mechanism (CALL INTRINSIC in COBOL) for the main
and all interacting parts of the application. Check the Pascal and
COBOL reference manuals for more information.
In all cases, check for any other use of the DL area by intrinsics
such as the DSG intrinsics.
