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EvmConnCreate(3)
Contents
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EvmConnCreate, EvmConnCreatePoster, EvmConnCreateSubscriber,
EvmConnFdGet, EvmConnDestroy - Establish or
destroy connection with the EVM daemon
#include <evm/evm.h>
EvmStatus_t EvmConnCreate(
EvmConnectionType_t type,
EvmResponseMode_t responseMode,
const EvmTransport_t transport,
EvmCallback_t callback,
EvmCallbackArg_t callbackArg,
EvmConnection_t *connection ); EvmStatus_t EvmConnCreatePoster(
EvmConnection_t *connection ); EvmStatus_t EvmConnCreateSubscriber(
EvmCallback_t callback,
EvmCallbackArg_t callbackArg,
EvmConnection_t *connection ); EvmStatus_t EvmConnFdGet(
EvmConnection_t connection,
EvmFd_t *fd ); EvmStatus_t EvmConnDestroy(
EvmConnection_t connection );
This operand establishes the function of the connection.
Possible values are the following: Creates a connection
for use by posting clients. Creates a connection for use
by subscribing clients. The responseMode operand must be
set to EvmRESPONSE_CALLBACK. Creates a service connection.
This mode is not currently supported for general
use. This operand establishes the behavior of certain
connection-oriented API functions when requests are made
to the EVM daemon. If a function call results in such a
request, the function will return a response according to
the value of this operand, as follows: The function
returns without waiting for the daemon's response. In this
mode, any return status other than EvmERROR_NONE indicates
that a problem was detected in preliminary validation. A
response of EvmERROR_NONE signifies only that the request
was sent to the daemon; you cannot establish whether it
was received or accepted. The function does preliminary
validation, returning a status reflecting any error it
finds. If it finds no error, it passes the request to the
EVM daemon and blocks until a response is received from
the daemon. The status returned by the function may result
either from preliminary validation or from validation by
the daemon. If no error is returned by the function, the
request has been accepted by the daemon. The function
returns without waiting for a response. Any return status
other than EvmERROR_NONE indicates that a problem was
detected in preliminary validation.
If no error is found, the function passes the
request to the EVM daemon, and returns immediately
with a status of EvmERROR_NONE. The calling process
must use EvmConnWait(3) or a related function
to watch for I/O activity on the connection, and
then invoke EvmConnDispatch(3) to handle the activity.
In most cases, this will result in the
connection's callback function being invoked to
handle incoming messages.
This response mode must be used for listening connections.
This specifies the type of connection to
be made to the daemon. You usually should set this
argument to NULL for the default connection to the
local daemon. For remote connection, set it to the
address of an EvmTransport_t structure, transport,
initialized in the following manner: transport.type
= EvmTRANSPORT_TCPIP; transport.data.tcpip.portNumber
= -1; /* -1 for default port */ transport.data.tcpip.hostName
= "remote_system_address";
A pointer to a routine that will be called by EvmConnDispatch()
to process an incoming message. The
routine must be declared as described in the EvmCallback(5) reference page. This operand should be
NULL if the response mode is not EvmRESPONSE_CALLBACK.
The argument that will be supplied as the
callbackArg argument each time the callback routine
is invoked by EvmConnDispatch(). See EvmCallback(5). The calling process should use this argument
to pass its own context data for the connection
to the callback function. This operand should
be NULL if no context data is required. For EvmConnCreate()
this is the return operand for the new
connection. For the other routines described on
this page, it is the connection to be processed.
The return operand for the file number associated
with the supplied connection.
The EvmConnCreate() routine establishes a connection
between a client process and the EVM daemon. If the connection
is successful, a pointer to a new connection context
is returned in the connection argument.
The EvmConnCreatePoster() routine is a macro that establishes
a posting connection to the local daemon. Using
this macro is equivalent to calling EvmConnCreate() with
type set to EvmCONNECTION_POST, responseMode set to EvmRESPONSE_WAIT,
and transport, callback and callbackArg all
set to NULL.
The EvmConnCreateSubscriber() routine is a macro that
establishes a subscribing connection to the local daemon.
Using this macro is equivalent to calling EvmConnCreate()
with type set to EvmCONNECTION_LISTEN, responseMode set to
EvmRESPONSE_CALLBACK, and transport set to NULL.
The EvmConnFdGet() routine returns the file number associated
with the connection. This file number can be used by
a client application, which handles multiple I/O sources,
for use in a call to select(2) to determine when there is
activity on the connection. The program must call EvmConnDispatch()
to handle the activity. It must not close the
file descriptor, nor perform any direct I/O on it.
The EvmConnDestroy() routine destroys the connection and
frees any resources associated with it. This routine must
be called to destroy the connection.
The operation was completed without error. One of the
arguments to the function was invalid. A value in a
structure member is invalid. An operation failed because
an attempt to acquire heap memory failed. A read error
occurred while reading from the EVM daemon connection. A
write error occurred while writing to the EVM daemon connection.
An error occurred while attempting to connect to
the EVM daemon. An error occurred on the EVM connection.
Invoke EvmConnDestroy() to destroy the connection. The
current operation was interrupted by receipt of a signal.
None
EVM Support Library (libevm.so, libevm.a)
Default pathname for the domain socket.
Commands: evmget(1), evmpost(1), evmwatch(1)
Functions: connect(2), select(2), socket(2)
Routines: EvmConnControl(3), EvmConnDispatch(3), EvmConnWait(3)
Files: kevm(7)
Event Management: EVM(5)
Event Callback: EvmCallback(5)
Event Connection: EvmConnection(5)
EVM Events: EvmEvent(5)
Programmer's Guide
EvmConnCreate(3)
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