1RECV(3PVM)                      PVM Version 3.4                     RECV(3PVM)
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NAME

6       pvm_recv - Receive a message.
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SYNOPSIS

10       C    int bufid = pvm_recv( int tid, int msgtag )
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12       Fortran   call pvmfrecv( tid, msgtag, bufid )
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PARAMETERS

16       tid     Integer  task  identifier  of  sending  process supplied by the
17               user.
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19       msgtag  Integer message tag supplied by the user.  msgtag should be  >=
20               0.
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22       bufid   Integer  returns  the  value  of  the new active receive buffer
23               identifier.  Values less than zero indicate an error.
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DESCRIPTION

27       The routine pvm_recv blocks the process until a message with label msg‐
28       tag  has  arrived  from tid.  pvm_recv then places the message in a new
29       active receive buffer, which also clears the current receive buffer.
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31       A -1 in msgtag or tid matches anything.  This allows the user the  fol‐
32       lowing  options.   If  tid = -1 and msgtag is defined by the user, then
33       pvm_recv will accept a message from any process which  has  a  matching
34       msgtag.   If  msgtag = -1 and tid is defined by the user, then pvm_recv
35       will accept any message that is sent from process tid.  If tid = -1 and
36       msgtag = -1, then pvm_recv will accept any message from any process.
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38       The  PVM model guarantees the following about message order.  If task 1
39       sends message A to task 2, then task 1 sends message B to task 2,  mes‐
40       sage  A will arrive at task 2 before message B.  Moreover, if both mes‐
41       sages arrive before task 2 does a receive, then a wildcard receive will
42       always return message A.
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44       If  pvm_recv  is  successful, bufid will be the value of the new active
45       receive buffer identifier.  If some error occurs then bufid will  be  <
46       0.
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48       pvm_recv  is  blocking  which  means  the routine waits until a message
49       matching the user specified tid and msgtag values arrives at the  local
50       pvmd.  If the message has already arrived then pvm_recv returns immedi‐
51       ately with the message.
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53       Once pvm_recv returns, the data in the message can be unpacked into the
54       user's memory using the unpack routines.
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EXAMPLES

58       C:
59            tid = pvm_parent();
60            msgtag = 4 ;
61            bufid = pvm_recv( tid, msgtag );
62            info = pvm_upkint( tid_array, 10, 1 );
63            info = pvm_upkint( problem_size, 1, 1 );
64            info = pvm_upkfloat( input_array, 100, 1 );
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66       Fortran:
67            CALL PVMFRECV( -1, 4, BUFID )
68            CALL PVMFUNPACK( INTEGER4, TIDS, 25, 1, INFO )
69            CALL PVMFUNPACK( REAL8, MATRIX, 100, 100, INFO )
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ERRORS

74       These error conditions can be returned by pvm_recv
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76       PvmBadParam
77              giving an invalid tid value, or msgtag < -1.
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79       PvmSysErr
80              pvmd not responding.
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SEE ALSO

83       pvm_bufinfo(3PVM),         pvm_getminfo(3PVM),         pvm_nrecv(3PVM),
84       pvm_unpack(3PVM), pvm_probe(3PVM), pvm_send(3PVM), pvm_mcast(3PVM)
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88                                30 August, 1993                     RECV(3PVM)
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