dat_cno_wait

- wait for notification events

Synopsis

cc [ flag… ] file… -ldat [ library… ] 
#include <dat/udat.h>

DAT_RETURN
    dat_cno_wait (
    IN    DAT_CNO_HANDLE    cno_handle,
    IN    DAT_TIMEOUT       timeout,
    OUT   DAT_EVD_HANDLE    *evd_handle
    )

Parameters

cno_handle

Handle for an instance of CNO

timeout

The duration to wait for a notification. The value DAT_TIMEOUT_INFINITE can be used to wait indefinitely.

evd_handle

Handle for an instance of EVD

Description

The dat_cno_wait() function allows the Consumer to wait for notification events from a set of Event Dispatchers all from the same Interface Adapter. The Consumer blocks until notified or the timeout period expires.

An Event Dispatcher that is disabled or in the "Waited" state does not deliver notifications. A uDAPL Consumer waiting directly upon an Event Dispatcher preempts the CNO.

The consumer can optionally specify a timeout, after which it is unblocked even if there are no notification events. On a timeout, evd_handle is explicitly set to a null handle.

The returned evd_handle is only a hint. Another Consumer can reap the Event before this Consumer can get around to checking the Event Dispatcher. Additionally, other Event Dispatchers feeding this CNO might have been notified. The Consumer is responsible for ensuring that all EVDs feeding this CNO are polled regardless of whether they are identified as the immediate cause of the CNO unblocking.

All the waiters on the CNO, including the OS Wait Proxy Agent if it is associated with the CNO, are unblocked with the NULL handle returns for an unblocking EVD evd_handle when the IA instance is destroyed or when all EVDs the CNO is associated with are freed.

Return Values

DAT_SUCCESS

The operation was successful.

DAT_INVALID_HANDLE

The cno_handle parameter is invalid.

DAT_QUEUE_EMPTY

The operation timed out without a notification.

DAT_INVALID_PARAMETER

One of the parameters was invalid or out of range, a combination of parameters was invalid, or the timeout parameter is invalid.

DAT_INTERRUPTED_CALL

The operation was interrupted by a signal.

Attributes

See attributes(5) for descriptions of the following attributes:

See Also

libdat(3LIB), attributes(5)