Linux and UNIX Man Pages

Linux & Unix Commands - Search Man Pages

pvm_recv(3pvm) [redhat man page]

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 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
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_unpack(3PVM), pvm_probe(3PVM), pvm_send(3PVM), pvm_mcast(3PVM) 30 August, 1993 RECV(3PVM)

Check Out this Related Man Page

PROBE(3PVM)							  PVM Version 3.4						       PROBE(3PVM)

NAME
pvm_probe - Check if message has arrived. SYNOPSIS
C int bufid = pvm_probe( int tid, int msgtag ) Fortran call pvmfprobe( 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_probe checks to see if a message with label msgtag has arrived from tid. If a matching message has arrived pvm_probe returns a buffer identifier in bufid. This bufid can be used with pvm_bufinfo to determine information about the message such as its source and length. If the requested message has not arrived, then pvm_probe 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_probe will accept a message from any process which has a matching msgtag. If msgtag = -1 and tid is defined by the user, then pvm_probe will accept any message that is sent from process tid. If tid = -1 and msgtag = -1, then pvm_probe will accept any message from any process. pvm_probe can be called multiple times to check if a given message has arrived yet. After the message has arrived, pvm_recv must be called before the message can be unpacked into the user's memory using the unpack routines. EXAMPLES
C: tid = pvm_parent(); msgtag = 4 ; arrived = pvm_probe( tid, msgtag ); if ( arrived ) info = pvm_bufinfo( arrived, &len, &tag, &tid ); else /* go do other computing */ Fortran: CALL PVMFPROBE( -1, 4, ARRIVED ) IF ( ARRIVED .GT. 0 ) THEN CALL PVMFBUFINFO( ARRIVED, LEN, TAG, TID, INFO ) ELSE * GO DO USEFUL WORK ENDIF ERRORS
These error conditions can be returned by pvm_probe. PvmBadParam giving an invalid tid value or msgtag. PvmSysErr pvmd not responding. SEE ALSO
pvm_bufinfo(3PVM), pvm_getminfo(3PVM), pvm_nrecv(3PVM), pvm_recv(3PVM), pvm_unpack(3PVM) 30 August, 1993 PROBE(3PVM)
Man Page