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RECV(3PVM) PVM Version 3.4 RECV(3PVM) 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 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 ALSO pvm_bufinfo(3PVM), pvm_getminfo(3PVM), pvm_nrecv(3PVM), pvm_un- pack(3PVM), pvm_probe(3PVM), pvm_send(3PVM), pvm_mcast(3PVM) 30 August, 1993 RECV(3PVM)
NAME | SYNOPSIS | PARAMETERS | DESCRIPTION | EXAMPLES | ERRORS | SEE ALSO
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