Ubuntu Manpage: pvm_recv - Receive a message.

NAME

       pvm_recv - Receive a message.

SYNOPSIS

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

       Fortran   call pvmfrecv( 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  returns  the  value  of the new active receive buffer identifier.  Values
               less than zero indicate an error.

DESCRIPTION

The routine pvm_recv blocks the process until a message with label msgtag has arrived from
tid. pvm_recv then places the message in a new active receive buffer, which also clears
the current receive buffer.

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_recv will accept a message from any
process which has a matching msgtag. If msgtag = -1 and tid is defined by the user, then
pvm_recv will accept any message that is sent from process tid. If tid = -1 and msgtag =
-1, then pvm_recv 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.

If pvm_recv is successful, bufid will be the value of the new active receive buffer
identifier. If some error occurs then bufid will be < 0.

pvm_recv is blocking which means the routine waits until a message matching the user
specified tid and msgtag values arrives at the local pvmd. If the message has already
arrived then pvm_recv returns immediately with the message.

Once pvm_recv returns, the data in the message can be unpacked into the user's memory
using the unpack routines.

EXAMPLES

       C:
            tid = pvm_parent();
            msgtag = 4 ;
            bufid = pvm_recv( tid, msgtag );
            info = pvm_upkint( tid_array, 10, 1 );
            info = pvm_upkint( problem_size, 1, 1 );
            info = pvm_upkfloat( input_array, 100, 1 );

       Fortran:
            CALL PVMFRECV( -1, 4, BUFID )
            CALL PVMFUNPACK( INTEGER4, TIDS, 25, 1, INFO )
            CALL PVMFUNPACK( REAL8, MATRIX, 100, 100, INFO )

ERRORS