pvm_send(3pvm) [redhat man page]

SEND(3PVM)							  PVM Version 3.4							SEND(3PVM)

NAME

       pvm_send - Immediately sends the data in the active message buffer.

SYNOPSIS

       C    int info = pvm_send( int tid, int msgtag )

       Fortran	 call pvmfsend( tid, msgtag, info )

PARAMETERS

       tid     Integer task identifier of destination process.

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

       info    Integer status code returned by the routine.

DESCRIPTION

       The  routine  pvm_send  sends a message stored in the active send buffer to the PVM process identified by tid.  msgtag is used to label the
       content of the message.	If pvm_send is successful, info will be 0. If some error occurs then info will be < 0.

       The pvm_send routine is asynchronous.  Computation on the sending processor resumes as soon as the message is safely  on  its  way  to  the
       receiving  processor.   This is in contrast to synchronous communication, during which computation on the sending processor halts until the
       matching receive is executed by the receiving processor.

       The PVM model guarantees the following about message order.  If task 1 sends message A to task 2, then task 1 sends message B  to  task	2,
       message	A will arrive at task 2 before message B.  Moreover, if both messages arrive before task 2 does a receive, then a wildcard receive
       will always return message A.

       Terminating a PVM task immediately after sending a message or messages from it may result in those messages being lost.	To be sure, always
       call pvm_exit() before stopping.

EXAMPLES

       C:
	    info = pvm_initsend( PvmDataDefault );
	    info = pvm_pkint( array, 10, 1 );
	    msgtag = 3 ;
	    info = pvm_send( tid, msgtag );

       Fortran:
	    CALL PVMFINITSEND(PVMRAW, INFO)
	    CALL PVMFPACK( REAL8, DATA, 100, 1, INFO )
	    CALL PVMFSEND( TID, 3, INFO )

ERRORS

       These error conditions can be returned by pvm_send

       PvmBadParam
	      giving an invalid tid or a msgtag.

       PvmSysErr
	      pvmd not responding.

       PvmNoBuf
	      no active send buffer. Try pvm_initsend() before send.

SEE ALSO

       pvm_initsend(3PVM), pvm_mcast(3PVM), pvm_pack(3PVM), pvm_psend(3PVM), pvm_recv(3PVM)

								  30 August, 1993							SEND(3PVM)

NRECV(3PVM)							  PVM Version 3.4						       NRECV(3PVM)

NAME

       pvm_nrecv - Non-blocking receive.

SYNOPSIS

       C    int bufid = pvm_nrecv( int tid, int msgtag )

       Fortran	 call pvmfnrecv( 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_nrecv	checks	to see if a message with label msgtag has arrived from tid.  and also clears the current receive buffer if
       any, If a matching message has arrived pvm_nrecv immediately places the message in a new active receive	buffer,  and  returns  the  buffer
       identifier in bufid.

       If the requested message has not arrived, then pvm_nrecv immediately 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 following options.  If tid = -1 and msgtag is defined by the user, then
       pvm_nrecv will accept a message from any process which has a matching msgtag.  If msgtag =  -1  and  tid  is  defined  by  the  user,  then
       pvm_nrecv  will accept any message that is sent from process tid.  If tid = -1 and msgtag = -1, then pvm_nrecv will accept any message from
       any process.

       The PVM model guarantees the following about message order.  If task 1 sends message A to task 2, then task 1 sends message B  to  task	2,
       message	A will arrive at task 2 before message B.  Moreover, if both messages arrive before task 2 does a receive, then a wildcard receive
       will always return message A.

       pvm_nrecv is non-blocking in the sense that the routine always returns immediately either with the message or with the information that the
       message	has  not  arrived  at the local pvmd yet.  pvm_nrecv can be called multiple times to check if a given message has arrived yet.	In
       addition the blocking receive pvm_recv can be called for the same message if the application runs out of work it could do before  the  data
       arrives.

       If pvm_nrecv returns with the message, then the data in the message can be unpacked into the user's memory using the unpack routines.

EXAMPLES

       C:
	    tid = pvm_parent();
	    msgtag = 4 ;
	    arrived = pvm_nrecv( tid, msgtag );
	    if ( arrived > 0)
		 info = pvm_upkint( tid_array, 10, 1 );
	    else
		 /* go do other computing */

       Fortran:
	    CALL PVMFNRECV( -1, 4, ARRIVED )
	    IF ( ARRIVED .gt. 0 ) THEN
	       CALL PVMFUNPACK( INTEGER4, TIDS, 25, 1, INFO )
	       CALL PVMFUNPACK( REAL8, MATRIX, 100, 100, INFO )
	    ELSE
       *       GO DO USEFUL WORK
	    ENDIF

ERRORS

       These error conditions can be returned by pvm_nrecv.

       PvmBadParam
	      giving an invalid tid value or msgtag.

       PvmSysErr
	      pvmd not responding.

SEE ALSO

       pvm_bufinfo(3PVM), pvm_getminfo(3PVM), pvm_recv(3PVM), pvm_unpack(3PVM), pvm_send(3PVM), pvm_mcast(3PVM)

								  30 August, 1993						       NRECV(3PVM)