evmconncheck(3) [hpux man page]
EvmConnCheck(3) Library Functions Manual EvmConnCheck(3) NAME
EvmConnCheck(), EvmConnWait(), EvmConnDispatch(), EvmConnFlush() - maintain connection with the EVM daemon SYNOPSIS
Library EVM Support Library Parameters connection The EVM connection that is to be monitored. See the EvmConnCreate(3) manpage. IOWaiting This is the return operand. Possible values for this operand are the following: There is no outstanding I/O activity on the connection. There is outstanding I/O activity on the connection. The client needs to call to handle the outstanding activity. timeout If the timeout value is NULL, it specifies that is to wait until there is activity on the connection. If the timeout value is not NULL, it specifies the amount of time that waits for activity on the connection. count Receives a count of messages queued for sending to the EVM daemon. DESCRIPTION
The routine checks whether there is any I/O activity outstanding on the connection. If there is activity, IOWaiting is set to The program is to then call to handle it. If there is no outstanding I/O activity, IOWaiting is set to An response from this function does not guaran- tee that an event has arrived. An response simply means that there is a message on the connection that needs to be handled. The routine blocks until activity is detected on the connection. If timeout is not NULL, it specifies the amount of time that the function waits for activity on the connection before returning with a status of The routine handles one incoming I/O message on the connection, calling the client's callback function as needed. If there is no message awaiting processing, the function returns immediately. Calling this function is not guaranteed to invoke the connection's callback func- tion. If the callback is invoked, it is not necessarily true that an event has arrived. The routine attempts to send to the EVM daemon any messages that are queued for output as a result of earlier calls on a connection that is marked as a non-blocking connection. The routine continues to send messages from the queue, until either all messages have been sent or until the send buffer is full. On return, if the count output parameter is a number greater than zero, then that number is the number of messages still queued for sending. returns See EvmConnControl(3) for more information. RETURN VALUE
The operation completed without error. One of the arguments to the function is 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 on the EVM connection. Invoke to destroy the connection. A timeout period expired. The current operation was interrupted by receipt of a signal. One or more messages is queued for sending to the EVM daemon. ERRORS
The value of is not set. FILES
Default pathname for the domain socket. SEE ALSO
Functions connect(2), select(2), socket(2). Routines EvmConnControl(3), EvmConnCreate(3), EvmConnDestroy(3), EvmEventPost(3). Event Management EVM(5). Event Callback EvmCallback(5). Event Connection EvmConnection(5). EVM Events EvmEvent(5). EvmConnCheck(3)
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EvmConnCreate(3) Library Functions Manual EvmConnCreate(3) NAME
EvmConnCreate(), EvmConnCreatePoster(), EvmConnCreateSubscriber(), EvmConnDestroy(), EvmConnFdGet() - establish or destroy connection with the EVM daemon SYNOPSIS
Library EVM Support Library Parameters type Establishes the function of the connection. Possible values are as follows: Creates a connection for use by posting clients. Creates a connection for use by subscribing clients. The responseMode operand must be set to responseMode Establishes the behavior of certain connection-oriented API functions when requests are made to the EVM daemon. If a func- tion call results in such a request, the function returns 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 indicates that a problem was detected in preliminary validation. A response of signifies only that the request was sent to the daemon. An response cannot determine if the request was received or accepted. The function does preliminary validation, returning a status reflecting any error it finds. If the function 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 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 The calling process must use or a related function to watch for I/O activity on the connection, and then invoke to handle the activity. In most cases, the connection's callback function is invoked to handle incoming messages. This response mode must be used for listening connections. transport Specify the type of connection to be made to the daemon. Because EVM currently supports only local connection the daemon, this argument must always be set to NULL. If this argument is not NULL, an error occurs. callback A pointer to a routine that is to be called by to process an incoming message. The routine is declared as described in the EvmCallback(5) manpage. If the response mode is not this operand is NULL. callbackArg This argument is supplied each time the callback routine is invoked by See EvmCallback(5). The calling process uses this argument to pass its own context data for the connection to the callback function. If no context data is required, this op- erand is NULL. connection For connection is the return operand for the new connection. For the other routines described on this manpage, connection is the EVM connection to be processed. fd The return operand for the file number associated with the supplied connection. DESCRIPTION
The routine establishes a connection between a client process and the EVM daemon. If the connection is successful, a pointer to a new con- nection context is returned in the connection argument. The routine is a macro that establishes a posting connection to the local daemon. Using this macro is equivalent to calling with type set to responseMode set to and transport, callback,and callbackArg are all set to NULL. The routine is a macro that establishes a subscribing connection to the local daemon. Using this macro is equivalent to calling with type set to responseMode set to and transport set to NULL. The 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 to determine when there is activity on the connection. The program must call to handle the activity. It must not close the file descriptor, nor perform any direct I/O on it. The routine destroys the connection and frees any resources associated with it. This routine must be called to destroy the connection. RETURN VALUE
The operation completed without error. One of the arguments to the function is 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 to destroy the connection. The current operation was interrupted by receipt of a signal. ERRORS
The value of is not set. FILES
Default pathname for the domain socket. SEE ALSO
Commands evmget(1), evmpost(1), evmwatch(1). Functions connect(2), select(2), socket(2). Routines EvmConnControl(3), EvmConnDispatch(3), EvmConnWait(3). Event Management EVM(5). Event Callback EvmCallback(5). Event Connection EvmConnection(5). EVM Events EvmEvent(5). EvmConnCreate(3)