ADVISE(3PVM) PVM Version 3.4 ADVISE(3PVM)NAMEpvm_advise() - Controls use of direct task-to-task routing.
[In Version 3.2: Replaced by pvm_setopt]
SYNOPSIS
C int info = pvm_advise( int route )
Fortran call pvmfadvise( route, info )
PARAMETERS
route Integer advising PVM to set up direct task-to-task links.
route options
PvmDontRoute 1 Don't allow direct links to this task
PvmAllowDirect 2 Allow but don't request direct links
PvmRouteDirect 3 Request direct links
info Integer returning error status.
DESCRIPTION
The routine pvm_advise advises PVM on whether or not to set up direct
task-to-task links (using TCP) for all subsequent communication. Once a
link is established it remains until the application finishes. If a
direct link can not be established because one of the two tasks has
requested PvmDontRoute or because no resources are available, then the
default route through the PVM daemons is used. pvm_advise can be
called multiple times to selectively establish direct links, but is
typically set only once near the beginning of each task. PvmAllowDi‐
rect is the default advise setting. This setting on task A allows
other tasks to set up direct links to A. Once a direct link is estab‐
lished between tasks both tasks will use it for sending messages.
pvm_advise returns the error status in info. The performance of direct
task-to-task links can be up to a factor of two better than the default
route. The draw back is a lack of scalability of the direct links.
Some versions of UNIX limit the number of links to no more than 30.
EXAMPLES
C:
info = pvm_advise( PvmRouteDirect );
Fortran:
CALL PVMFADVISE( PVMROUTEDIRECT, INFO )
ERRORS
This error condition can be returned by pvm_advise
PvmBadParam
giving an invalid route value.
SEE ALSOpvm_setopt(3PVM)
30 August, 1993 ADVISE(3PVM)
