Enable Cancellation Detection

This Subprogram enables Cancellation detection. If the Operator subsequently types ``Ctrl-C" (presses the C key whilst simultaneously holding down the CONTROL or CTRL key) this will cause an internal cancellation flag to be set. This flag can either be tested (via UI_TEST_CANCEL) or may cause a User-supplied Subroutine to be called.

This Feature only implemented
for VAX/VMS Systems in Text Mode

Short Name Calling Sequence

STATUS = UIENCA([OLDCAN])

Long Name Calling Sequence

STATUS = UI_ENABLE_CANCEL(...)

Input Arguments

None

Output Arguments

OLDCAN (Logical) Old Cancel Mode (Optional)

Function Value

UI__SUCCESS ) Success UISUCC )

UI__NOT_INITIALIZED ) Package not Initialized UININI )

Note:

1. This call will be ignored if Cancellation detection is already enabled.
2. Cancellation Detection is initially disabled.
3. The OLDCAN Argument is optional and, if present, will be set to the old Cancellation Detection Status (.TRUE. or .FALSE.) prior to this call.