Provided by: pvm-dev_3.4.5-12.6ubuntu1_amd64 bug


       pvm_nrecv - Non-blocking receive.


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

       Fortran   call pvmfnrecv( tid, msgtag, bufid )


       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.


       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.


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

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


       These error conditions can be returned by pvm_nrecv.

              giving an invalid tid value or msgtag.

              pvmd not responding.


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

                                         30 August, 1993                              NRECV(3PVM)