Tribblix: manual page: dat_ep_set

DAT_EP_SET_WATERMARK(3DAT) Direct Access Transport Library Functions

NAME

dat_ep_set_watermark - set high watermark on Endpoint

SYNOPSIS

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

DAT_RETURN
dat_ep_set_watermark (
IN DAT_EP_HANDLE ep_handle,
IN DAT_COUNT soft_high_watermark,
IN DAT_COUNT hard_high_watermark
)

PARAMETERS

ep_handle
The handle for an instance of an Endpoint.

soft_high_watermark
The soft high watermark for the number of Recv
buffers consumed by the Endpoint.

hard_high_watermark
The hard high watermark for the number of Recv
buffers consumed by the Endpoint.

DESCRIPTION

The dat_ep_set_watermark() function sets the soft and hard high
watermark values for EP and arms EP for generating asynchronous
events for high watermarks. An asynchronous event will be generated
for IA async_evd when the number of Recv buffers at EP exceeds the
soft high watermark for the first time. A connection broken event
will be generated for EP connect_evd when the number of Recv buffers
at EP exceeds the hard high watermark. These can occur during this
call or when EP takes a buffer from the SRQ or EP RQ. The soft and
hard high watermark asynchronous event generation and setting are
independent of each other.

The asynchronous event for a soft high watermark is generated only
once per setting. Once an event is generated, no new asynchronous
events for the soft high watermark is generated until the EP is again
set for the soft high watermark. If the Consumer is once again
interested in the event, the Consumer should again set the soft high
watermark.

If the Consumer is not interested in a soft or hard high watermark,
the value of DAT_WATERMARK_INFINITE can be specified for the case
that is the default value. This value specifies that a non-
asynchronous event will be generated for a high watermark EP
attribute for which this value is set. It does not prevent generation
of a connection broken event for EP when no Recv buffer is available
for a message arrived on the EP connection.

The operation is supported for all states of Endpoint.

RETURN VALUES

DAT_SUCCESS
The operation was successful.

DAT_INVALID_HANDLE
The ep_handle argument is an invalid DAT
handle.

DAT_INVALID_PARAMETER
One of the parameters is invalid.

DAT_MODEL_NOT_SUPPORTED
The requested Model was not supported by
the Provider. The Provider does not
support EP Soft or Hard High Watermarks.

USAGE

For a hard high watermark, the Provider is ready to generate a
connection broken event as soon as the connection is established.

If the asynchronous event for a soft or hard high watermark has not
yet been generated, this call simply modifies the values for these
attributes. The Provider remains armed for generation of these
asynchronous events.

Regardless of whether an asynchronous event for the soft and hard
high watermark has been generated, this operation will set the
generation of an asynchronous event with the Consumer-provided high
watermark values. If the new high watermark values are below the
current number of Receive DTOs at EP, an asynchronous event will be
generated immediately. Otherwise the old soft or hard (or both) high
watermark values are simply replaced with the new ones.

ATTRIBUTES