Specifications

Operating System Routines
COM$DELATTNAST
COM$DELATTNAST
Delivers all attention ASTs linked in the specified list.
Module
COMDRVSUB
Input
Location Contents
R4 Address of listhead of AST control blocks
R5 Address of UCB
Output
Location Contents
Specified listhead Empty
R0 through R11 Preserved
Synchronization
COM$DELATTNAST executes and exits at the caller’s IPL, and acquires no
spinlocks. However, the caller must be executing at IPL3 or higher to avoid
certain race conditions.
Description
COM$DELATTNAST removes all AST control blocks (ACBs) from the specified
list. Using each ACB as a fork block, it schedules a fork process at IPL$_
QUEUEAST to queue the AST to its target process. COM$DELATTNAST
dequeues each ACB from the head of the list, thus removing them in the
reverse order of their declaration by COM$SETATTNAST. Note that in certain
circumstances attention ASTs can be delivered to a user process before the
delivery of I/O completion ASTs previously posted by the driver.
3–4