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PROBE(3PVM)			PVM Version 3.4			   PROBE(3PVM)

NAME
       pvm_probe - Check if message has	arrived.

SYNOPSIS
       C    int	bufid =	pvm_probe( int tid, int	msgtag )

       Fortran	 call pvmfprobe( tid, msgtag, bufid )

PARAMETERS
       tid     Integer	task  identifier  of  sending  process supplied	by the
	       user.

       msgtag  Integer message tag supplied by the user.  msgtag should	be  >=
	       0.

       bufid   Integer	returning  the	value of the new active	receive	buffer
	       identifier.  Values less	than zero indicate an error.

DESCRIPTION
       The routine pvm_probe checks to see if a	message	with label msgtag  has
       arrived	from tid.  If a	matching message has arrived pvm_probe returns
       a buffer	identifier in bufid.  This bufid can be	used with  pvm_bufinfo
       to  determine  information  about  the  message	such as	its source and
       length.

       If the requested	message	has not	arrived, then pvm_probe	returns	with a
       0 in bufid.  If some error occurs bufid will be < 0.

       A  -1 in	msgtag or tid matches anything.	 This allows the user the fol-
       lowing options.	If tid = -1 and	msgtag is defined by  the  user,  then
       pvm_probe  will	accept a message from any process which	has a matching
       msgtag.	If msgtag = -1 and tid is defined by the user, then  pvm_probe
       will accept any message that is sent from process tid.  If tid =	-1 and
       msgtag =	-1, then pvm_probe will	accept any message from	any process.

       pvm_probe can be	called multiple	times to check if a given message  has
       arrived yet. After the message has arrived, pvm_recv must be called be-
       fore the	message	can be unpacked	into the user's	memory using  the  un-
       pack routines.

EXAMPLES
       C:
	    tid	= pvm_parent();
	    msgtag = 4 ;
	    arrived = pvm_probe( tid, msgtag );
	    if ( arrived )
		 info =	pvm_bufinfo( arrived, &len, &tag, &tid );
	    else
		 /* go do other	computing */

       Fortran:
	    CALL PVMFPROBE( -1,	4, ARRIVED )
	    IF ( ARRIVED .GT. 0	) THEN
		 CALL PVMFBUFINFO( ARRIVED, LEN, TAG, TID, INFO	)
	    ELSE
       *	 GO DO USEFUL WORK
	    ENDIF

ERRORS
       These error conditions can be returned by pvm_probe.

       PvmBadParam
	      giving an	invalid	tid value or msgtag.

       PvmSysErr
	      pvmd not responding.

SEE ALSO
       pvm_bufinfo(3PVM), pvm_getminfo(3PVM), pvm_nrecv(3PVM), pvm_recv(3PVM),
       pvm_unpack(3PVM)

				30 August, 1993			   PROBE(3PVM)

NAME | SYNOPSIS | PARAMETERS | DESCRIPTION | EXAMPLES | ERRORS | SEE ALSO

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