RECV(3PVM) PVM Version 3.4 RECV(3PVM)NAMEpvm_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 msg‐
tag 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 fol‐
lowing 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, mes‐
sage A will arrive at task 2 before message B. Moreover, if both mes‐
sages 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 immedi‐
ately 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
These error conditions can be returned by pvm_recv
PvmBadParam
giving an invalid tid value, or msgtag < -1.
PvmSysErr
pvmd not responding.
SEE ALSOpvm_bufinfo(3PVM), pvm_getminfo(3PVM), pvm_nrecv(3PVM),
pvm_unpack(3PVM), pvm_probe(3PVM), pvm_send(3PVM), pvm_mcast(3PVM)
30 August, 1993 RECV(3PVM)
