NET/MASTER Network Control Language (NCL) Programmer's Guide

System-Defined Error Handlers for Specific Conditions
Run-Time Error Handling
7–26 106160 Tandem Computers Incorporated
See Section 14, “Working With Panels,” for more information on using panels and the
END function key.
The PANEL_ERROR Error
Handler
If present, the PANEL_ERROR error handler is invoked as a consequence of panel
validation processing by Panel Services, for example, attempting to display a panel
that does not exist. This error handler is set by the following ON statement:
ON PANEL_ERROR statement
See Section 14, “Working With Panels,” for more information on using panels.
The PANEL_RETURN Error
Handler
If present, the PANEL_RETURN error handler is invoked as a result of using the
PANEL verb when CONTROL NOPFK is set. It occurs when a user uses the RETURN
function key to remove a panel from display: that is, the user presses the F4 or SF16
function key on a Tandem 6530 or compatible terminal or the PF04 or PF16 function
key on an IBM 3270 or compatible terminal.
In a hierarchy of panels, the purpose of the RETURN function key is to allow a user to
move to the top panel in the hierarchy. Depending on the setting of the system
variable &SYS.PANEL.SKIP, the top panel can be redisplayed or options
“automatically” taken that call sub-panels.
This error handler is set by the following ON statement:
ON PANEL_RETURN statement
See Section 14, “Working With Panels,” for more information on using panels and the
RETURN function key.
The PANEL_SKIP_PMENU
Error Handler
A primary menu is a menu that an NCL process considers to be the top-level menu for
the current function. If present, the PANEL_SKIP_PMENU error handler is invoked
when a primary menu panel skip operation is detected. This occurs when a user
enters a value in the form =[ n [.n … ] ] into an input field defined as a field that can
accept primary menu panel skip requests. The #FLD PSKIP=PMENU statement in a
panel description file defines this type of input field. (This is the default for input
fields.)
Regarding a panel as the top-level menu allows a user to specify a panel skip
operation that starts from the top level menu rather than the currently displayed
panel. The equal sign (=) starts the panel skip from the top-level menu. The panel
skip operation then skips down the menu hierarchy using the specified menu options.
The &SYS.PANEL.SKIP system variable is set as a result of having a panel skip
attribute assigned to an input field.
This error handler is set by the following ON statement:
ON PANEL_SKIP_PMENU statement
See Section 14, “Working With Panels,” for more information on using panels and
panel skipping.