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)