NOTIFY(3PVM) PVM Version 3.4 NOTIFY(3PVM)NAME
pvm_notify - Request notification of PVM event such as host failure.
SYNOPSIS
C int info = pvm_notify( int what, int msgtag, int cnt, int *tids )
Fortran call pvmfnotify( what, msgtag, cnt, tids, info )
PARAMETERS
what Type of event to trigger the notification. Presently one of:
Value Meaning
PvmTaskExit Task exits or is killed
PvmHostDelete Host is deleted or crashes
PvmHostAdd New host is added
msgtag Message tag to be used in notification.
cnt For PvmTaskExit and PvmHostDelete, specifies the length of the
tids array. For PvmHostAdd, specifies the number of times to
notify.
tids For PvmTaskExit and PvmHostDelete, an array of length cnt of
task or pvmd TIDs to be notified about. The array is not used
with the PvmHostAdd option.
info Integer status code returned by the routine. Values less than
zero indicate an error.
DESCRIPTION
The routine pvm_notify requests PVM to notify the caller on detecting
certain events. One or more notify messages (see below) are sent by
PVM back to the calling task. The messages have tag msgtag supplied to
notify.
The notification messages have the following format:
PvmTaskExit
One notify message for each TID requested. The message body
contains a single TID of exited task.
PvmHostDelete
One notify message for each TID requested. The message body
contains a single pvmd-TID of exited pvmd.
PvmHostAdd
cnt notify messages are sent, one each time the local pvmd's
host table is updated. The message body contains an integer
length followed by a list of pvmd-TIDs of new pvmds. The
counter of PvmHostAdd messages yet to be sent is replaced by
successive calls to pvm_notify. Specifying a cnt of -1 turns on
PvmHostAdd messages until a future notify; a count of zero dis‐
ables them.
TIDs in the notify messages are packed as integers.
The calling task is responsible for receiving messages with the speci‐
fied tag and taking appropriate action.
Future versions of PVM may expand the list of available notification
events.
EXAMPLES
C:
info = pvm_notify( PvmTaskExit, 9999, ntask, tids );
Fortran:
CALL PVMFNOTIFY( PVMHOSTDELETE, 1111, NUMHOSTS, DTIDS, INFO )
To "cancel" a notify request in PVM, the pvm_notify routine can be re-
invoked with an additional PvmNotifyCancel flag in the what argument.
The remaining arguments to this cancelling invocation must match the
original invocation exactly, aside from the additional PvmNotifyCancel
which can be added(+) or OR-ed(|) to the what argument:
pvm_notify( PvmTaskExit, 9999, ntask, tids );
. . .
pvm_notify( PvmTaskExit | PvmNotifyCancel, 9999, ntask, tids );
Note that when a notify is cancelled, the notify message is delivered,
as if the given event (i.e. task exit, host add or delete) had
occurred.
ERRORS
PvmSysErr
pvmd not responding.
PvmBadParam
giving an invalid argument value.
SEE ALSOpvm_tasks(3PVM), pvm_config(3PVM)
31 January, 1994 NOTIFY(3PVM)
