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EvmConnWait(3)
NAME
  EvmConnCheck, EvmConnWait, EvmConnDispatch, EvmConnFlush - Maintains
  connection with the EVM daemon

LIBRARY
  EVM Support Library (libevm.so, libevm.a)

SYNOPSIS
  #include <sys/time.h>
  #include <evm/evm.h>

  EvmStatus_t EvmConnCheck (
	  EvmConnection_t connection,
	  EvmBoolean_t *IOWaiting);

  EvmStatus_t EvmConnWait (
	  EvmConnection_t connection,
	  const struct timeval *timeout);

  EvmStatus_t EvmConnDispatch (
	  EvmConnection_t connection);

  EvmStatus_t EvmConnFlush (
	  EvmConnection_t connection);
	  EvmInt32_t *count);

OPERANDS
  connection
	The EVM connection that is to be monitored.

  IOWaiting
	This is the return parameter.  Possible values for this parameter are
	the following:

	EvmFALSE
	      There is no outstanding I/O activity on the connection.

	EvmTRUE
	      There is outstanding I/O activity on the connection.  The
	      client should call EvmConnDispatch() to handle the outstanding
	      activity.

  timeout
	If this value is NULL, it specifies that EvmConnWait() should wait
	until there is activity on the connection.  If this value is not
	NULL, it specifies the amount of time that EvmConnWait() should wait
	for activity on the connection.

  count Receives a count of messages queued for sending to the EVM daemon.

DESCRIPTION
  The EvmConnCheck() routine checks whether there is any I/O activity
  outstanding on the connection.  If there is, IOWaiting is set to EvmTRUE.
  The program should then call EvmConnDispatch() to handle it.	If there is
  no outstanding I/O activity, IOWaiting is set to EvmFALSE.  A response
  EvmTRUE from this function does not guarantee that an event has arrived;
  simply that there is a message on the connection that needs to be handled.

  The EvmConnWait() routine blocks until activity is detected on the
  connection.  If timeout is not NULL, it specifies the amount of time that
  the function should wait for activity on the connection before returning
  with a status of EvmERROR_TIMEOUT.

  The EvmConnDispatch() routine will handle 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
  function, and if the callback is invoked, it is not necessarily true that
  an event has arrived.

  The EvmConnFlush() routine attempts to send to the EVM daemon any messages
  that are queued for output as a result of earlier EvmEventPost 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 the send buffer is full.	 On return, the count output
  parameter holds the number of messages still queued for sending; if this
  number is more than zero, EvmConnFlush returns EvmERROR_QUEUED.   See the
  EvmConnControl(3) reference page for more information.

RETURN VALUES
  EvmERROR_NONE
	A value in a structure member is invalid.

  EvmERROR_INVALID_ARGUMENT
	One of the arguments to the function was invalid.

  EvmERROR_INVALID_VALUE
	A value in a structure member is invalid.

  EvmERROR_NO_MEMORY
	An operation failed because an attempt to acquire heap memory failed.

  EvmERROR_READ
	A read error occurred while reading from the EVM daemon connection.

  EvmERROR_WRITE
	A write error occurred while writing to the EVM daemon connection.

  EvmERROR_SELECT
	An error occurred on the EVM connection. Invoke EvmConnDestroy() to
	destroy the connection.

  EvmERROR_TIMEOUT
	A timeout period expired.

  EvmERROR_SIGNAL
	The current operation was interrupted by receipt of a signal.

  EvmERROR_QUEUED
	One or more messages is queued for sending to the EVM daemon.



ERRORS
  None



FILES
  /var/evm/sockets/evmd
	    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)

Index for Section 3

Alphabetical listing for E

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