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

6       pvm_notify - Request notification of PVM event such as host failure.
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SYNOPSIS

10       C    int info = pvm_notify( int what, int msgtag, int cnt, int *tids )
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12       Fortran   call pvmfnotify( what, msgtag, cnt, tids, info )
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PARAMETERS

16       what    Type of event to trigger the notification.  Presently one of:
17                    Value               Meaning
18                    PvmTaskExit         Task exits or is killed
19                    PvmHostDelete       Host is deleted or crashes
20                    PvmHostAdd          New host is added
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22       msgtag  Message tag to be used in notification.
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24       cnt     For  PvmTaskExit and PvmHostDelete, specifies the length of the
25               tids array.  For PvmHostAdd, specifies the number of  times  to
26               notify.
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28       tids    For  PvmTaskExit  and  PvmHostDelete, an array of length cnt of
29               task or pvmd TIDs to be notified about.  The array is not  used
30               with the PvmHostAdd option.
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32       info    Integer  status code returned by the routine.  Values less than
33               zero indicate an error.
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DESCRIPTION

37       The routine pvm_notify requests PVM to notify the caller  on  detecting
38       certain  events.   One  or more notify messages (see below) are sent by
39       PVM back to the calling task.  The messages have tag msgtag supplied to
40       notify.
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42       The notification messages have the following format:
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44       PvmTaskExit
45              One  notify  message  for  each TID requested.  The message body
46              contains a single TID of exited task.
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49       PvmHostDelete
50              One notify message for each TID  requested.   The  message  body
51              contains a single pvmd-TID of exited pvmd.
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54       PvmHostAdd
55              cnt  notify  messages  are  sent, one each time the local pvmd's
56              host table is updated.  The message  body  contains  an  integer
57              length  followed  by  a  list  of  pvmd-TIDs  of new pvmds.  The
58              counter of PvmHostAdd messages yet to be  sent  is  replaced  by
59              successive calls to pvm_notify.  Specifying a cnt of -1 turns on
60              PvmHostAdd messages until a future notify; a count of zero  dis‐
61              ables them.
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63       TIDs in the notify messages are packed as integers.
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65       The  calling task is responsible for receiving messages with the speci‐
66       fied tag and taking appropriate action.
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68       Future versions of PVM may expand the list  of  available  notification
69       events.
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EXAMPLES

73       C:
74            info = pvm_notify( PvmTaskExit, 9999, ntask, tids );
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76       Fortran:
77            CALL PVMFNOTIFY( PVMHOSTDELETE, 1111, NUMHOSTS, DTIDS, INFO )
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80       To  "cancel" a notify request in PVM, the pvm_notify routine can be re-
81       invoked with an additional PvmNotifyCancel flag in the  what  argument.
82       The  remaining  arguments  to this cancelling invocation must match the
83       original invocation exactly, aside from the additional  PvmNotifyCancel
84       which can be added(+) or OR-ed(|) to the what argument:
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86            pvm_notify( PvmTaskExit, 9999, ntask, tids );
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88            . . .
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90            pvm_notify( PvmTaskExit | PvmNotifyCancel, 9999, ntask, tids );
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92       Note  that when a notify is cancelled, the notify message is delivered,
93       as if the given  event  (i.e.  task  exit,  host  add  or  delete)  had
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ERRORS

98       PvmSysErr
99              pvmd not responding.
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101       PvmBadParam
102              giving an invalid argument value.
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SEE ALSO

105       pvm_tasks(3PVM), pvm_config(3PVM)
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109                               31 January, 1994                   NOTIFY(3PVM)