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

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 operand. Possible values for this operand 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
  EvmConnControl(3) for more information.

RETURN VALUES
  EvmERROR_NONE
      The operation was completed without error.

  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

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

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)

  Files: kevm(7)

  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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