Specifications

Using Callable System Routines
10.3 System Services
Table 10–3 summarizes the system services according to their functions.
Table 10–3 Summary of System Services
Service Function
AST Services
$DCLAST Queues an AST for the calling access mode or for a less
privileged access mode.
$SETAST Enables or disables the delivery of asynchronous system
traps (ASTs) for the access mode from which the service
call is issued.
$SETPRA Establishes a routine to receive control after a power
recovery is detected.
$SYNCH Checks the completion status of a system service that
completes asynchronously.
Cluster Event Notification Services
‡$CLRCLUEVT Removes one or more notification requests previously
established by a call to $SETCLUEVT.
‡$SETCLUEVT Establishes a request for notification when a cluster
configuration event occurs.
‡$TSTCLUEVT Simulates the occurrence of a cluster configuration event
to test the functionality of the notification AST.
Condition-Handling Services
$DCLCMH Specifies the address of a routine to receive control when
a Change Mode to User or Change Mode to Supervisor
instruction trap occurs.
‡$GOTO_UNWIND Unwinds the call stack.
†$RELEASE_VP Terminates the current process’s status as a vector
consumer.
†$RESTORE_VP_EXCEPTION Restores the saved exception state of the vector processor.
†$RESTORE_VP_STATE Allows an AST routine or condition handler to restore the
vector state of the mainline routine.
†$SAVE_VP_EXCEPTION Saves the pending exception state of the vector processor.
$SETEXV Assigns a condition handler address to the primary,
secondary, or last chance exception vectors, or removes
a previously assigned handler address from any of these
three vectors.
$UNWIND Unwinds the procedure call stack.
DECdtm Services
$ABORT_TRANS (and $ABORT_TRANSW) Ends a transaction by aborting it (and wait).
$END_TRANS (and $END_TRANSW) Ends a transaction by attempting to commit it, and
returns the outcome of the transaction (and wait).
†VAX specific
‡AXP specific
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10–7