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BCAST

BCAST

Section: PVM Version 3.4 (3PVM) Updated: 30 August, 1993
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NAME

pvm_bcast - Broadcasts the data in the active message buffer to a group of processes.

 

SYNOPSIS

C       int info = pvm_bcast( char *group, int msgtag )

Fortran call pvmfbcast( group, msgtag, info )

 

PARAMETERS

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.

 

DESCRIPTION

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.

 

EXAMPLES

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 )

 

ERRORS

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.

 

SEE ALSO

pvm_joingroup(3PVM)


 

Index

NAME
SYNOPSIS
PARAMETERS
DESCRIPTION
EXAMPLES
ERRORS
SEE ALSO

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Time: 21:53:18 GMT, April 16, 2011