evmconnection.5 (2010 09)

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EvmConnection(5) EvmConnection(5)

NAME

EvmConnection - connection to the EVM (Event Management) daemon

DESCRIPTION

An EVM connection is the context through which data is passed to and from the EVM daemon. A connec-

tion has the following attributes:

• Connection Type

• Response Mode

• Transport Type

• Callback, and associated Callback Argument

• Connection Context

These attributes are described in the following sections.

An EVM client is any program that processes events through the EVM daemon. EVM supports three dis-

tinct types of client: posting clients, subscribing (listening) clients, and service clients. Regardless of type,

all clients connect to the EVM daemon in the same way.

Connection Type

The type of connection established determines the client type. There are associated constants to be used

when the connection is created.

Posting Connection (EvmCONNECTION_POST)

The client uses this connection to post events to the daemon for distribution.

Listening Connection (EvmCONNECTION_LISTEN)

The client uses this connection to listen for events distributed by the daemon.

Service Connection (EvmCONNECTION_SERVICE)

The client uses this connection to request that the daemon provide a service, such as retrieve

events from a log.

A client may use all three types of connection, but must establish each connection separately.

Response Mode

The response mode associated with a connection determines the manner in which certain API functions

will deal with the daemon’s responses to request messages. See the EvmConnCreate (3) reference page for

full details of each mode. The modes are:

Ignore (EvmRESPONSE_IGNORE)

The API functions will return as soon as the request has been sent to the daemon, and the

caller will not receive the daemon’s response.

Wait (EvmRESPONSE_WAIT)

The API functions will send the request to the daemon, and wait until a response has been

received before returning to the caller. The returned status code will reﬂect the response.

Callback (EvmRESPONSE_CALLBACK)

The API functions will return as soon as the request has been sent to the daemon, and the

caller must monitor the connection for a response. When the response is received, the

connection’s callback function will be invoked to handle it.

Transport Type

The transport type speciﬁes the type of connection to be made to the daemon. The only valid connection

that can be made is:

Local Connection (EvmTRANSPORT_DOMAIN_SOCKET)

Connection is through a domain socket to a daemon running on the local host.

Callback

This attribute speciﬁes the function you want to handle any incoming responses resulting from activity on

the connection. Callbacks are discussed in more detail in the EvmCallback (5) reference page. This attri-

bute is valid only when the Response Mode is

EvmRESPONSE_CALLBACK.

HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1

Summary of content (2 pages)

PAGE 1
EvmConnection(5) EvmConnection(5) NAME EvmConnection - connection to the EVM (Event Management) daemon DESCRIPTION An EVM connection is the context through which data is passed to and from the EVM daemon. A connection has the following attributes: • Connection Type • Response Mode • Transport Type • Callback, and associated Callback Argument • Connection Context These attributes are described in the following sections. An EVM client is any program that processes events through the EVM daemon.
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EvmConnection(5) EvmConnection(5) Connection Context This attribute is a handle to a connection returned when a connection is created. You must pass this handle to all other functions you call which need to access the connection. Connection Monitoring Once you have established a connection, the API functions will take care of all communication activity with the daemon. However, you must make sure that these functions get an opportunity to do their work when activity occurs.