Define User AST Subroutine

This Subprogram allows an Application Programmer to define a Subroutine that will be called automatically when Asynchronous Input is detected. The Subprogram will be called at AST level on VAX/VMS Systems and cannot have any arguments.

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

Short Name Calling Sequence

STATUS = UIDFAS(USRSUB)

Long Name Calling Sequence

STATUS = UI_DEFINE_AST(...)

Input Arguments

USRSUB (see notes) User Subroutine Name

Output Arguments

None

Function Value

UI__SUCCESS ) Success UISUCC )

UI__NOT_INITIALIZED ) Package not Initialized UININI )

Note:

1. The USRSUB Argument should be the name of the required Subroutine and must be declared EXTERNAL within the calling program.
2. The specified Subroutine will be called automatically at AST level. It may be used, for example, to call the appropriate DAQ Package (CDF-166) Subprograms to cancel a pending ``Get Event" or ``Get Space" request and re-activate the process.