pvm_bcast - Broadcasts the data in the active message buffer to a group of
processes.
C int info = pvm_bcast( char *group, int msgtag )
Fortran call pvmfbcast( group, msgtag, info )
- group
- Character string group name of an existing group.
- msgtag
- Integer message tag supplied by the user. msgtag should be >= 0. It
allows the user's program to distinguish between different kinds of
messages .
info integer status code returned by the routine. Values less than
zero indicate an error.
The routine pvm_bcast broadcasts a message stored in the active send
buffer to all the members of group. In PVM 3.2 and later the broadcast
message is not sent back to the sender. Any PVM task can call pvm_bcast(), it
need not be a member of the group. The content of the message can be
distinguished by msgtag. If pvm_bcast is successful, info will
be 0. If some error occurs then info will be < 0.
pvm_bcast is asynchronous. Computation on the sending processor
resumes as soon as the message is safely on its way to the receiving
processors. This is in contrast to synchronous communication, during which
computation on the sending processor halts until a matching receive is
executed by all the receiving processors.
pvm_bcast first determines the tids of the group members by
checking a group data base. A multicast is performed to these tids. If the
group is changed during a broadcast the change will not be reflected in the
broadcast. Multicasting is not supported by most multiprocessor vendors.
Typically their native calls only support broadcasting to all the
user's processes on a multiprocessor. Because of this omission, pvm_bcast
may not be an efficient communication method on some multiprocessors.
C:
info = pvm_initsend( PvmDataRaw );
info = pvm_pkint( array, 10, 1 );
msgtag = 5 ;
info = pvm_bcast( "worker", msgtag );
Fortran:
CALL PVMFINITSEND( PVMDEFAULT )
CALL PVMFPKFLOAT( DATA, 100, 1, INFO )
CALL PVMFBCAST( 'worker', 5, INFO )
These error conditions can be returned by pvm_bcast
- PvmSysErr
- pvmd was not started or has crashed.
- PvmBadParam
- giving a negative msgtag.
- PvmNoGroup
- giving a non-existent group name.