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pvm_tasks(3pvm) [debian man page]

TASKS(3PVM)							  PVM Version 3.4						       TASKS(3PVM)

pvm_tasks - Returns information about the tasks running on the virtual machine. SYNOPSIS
C int info = pvm_tasks( int where, int *ntask, struct pvmtaskinfo **taskp ) struct pvmtaskinfo { int ti_tid; int ti_ptid; int ti_host; int ti_flag; char *ti_a_out; } taskp; Fortran call pvmftasks( where, ntask, tid, ptid, dtid, flag, aout, info ) PARAMETERS
where Integer specifying what tasks to return information about. The options are: 0 for all the tasks on the virtual machine pvmd tid for all tasks on a given host tid for a specific task ntask Integer returning the number of tasks being reported on. taskp Returns pointer to an array of structures which contain information about each task including its task ID, parent tid, pvmd task ID, status flag, and the name of this task's executable file. The status flag values are: waiting for a message, waiting for the pvmd, and running. tid Integer returning task ID of one task ptid Integer returning parent task ID dtid Integer returning pvmd task ID of host task is on. flag Integer returning status of task aout Character string returning the name of spawned task. Manually started tasks return blank. info Integer status code returned by the routine. Values less than zero indicate an error. DESCRIPTION
The routine pvm_tasks returns information about tasks presently running on the virtual machine. The information returned is the same as that available from the console command ps. The C function returns information about the entire virtual machine in one call. The Fortran function returns information about one task per call and cycles through all the tasks. Thus, if where = 0, and pvmftasks is called ntask times, all tasks will be represented. Note that in Fortran the reported value of ntask and the set of tasks do not change until the function resets at the end of a complete cycle. The user can reset pvmftasks() at any time by calling it with ntask = -1. If pvm_tasks is successful, info will be 0. If some error occurs then info will be < 0. EXAMPLES
C: struct pvmtaskinfo *taskp; int i, ntask; info = pvm_tasks( 0, &ntask, &taskp ); for (i = 0; i < ntask; i++) printf("t%x ", taskp[i].ti_tid); Fortran: Do i=1, NTASK CALL PVMFTASKS( DTID, NTASK, TID(i), PTID(i), DTID(i), & FLAG(i), AOUT(i), INFO ) EndDo ERRORS
The following error condition can be returned by pvm_tasks PvmBadParam invalid value for where argument. PvmSysErr pvmd not responding. PvmNoHost specified host not in virtual machine. SEE ALSO
pvm_config(3PVM), pvm_tidtohost(3PVM) 31 August, 1994 TASKS(3PVM)

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MCAST(3PVM)							  PVM Version 3.4						       MCAST(3PVM)

pvm_mcast - Multicasts the data in the active message buffer to a set of tasks. SYNOPSIS
C int info = pvm_mcast( int *tids, int ntask, int msgtag ) Fortran call pvmfmcast( ntask, tids, msgtag, info ) PARAMETERS
ntask Integer specifying the number of tasks to be sent to. tids Integer array of length ntask containing the task IDs of the tasks to be sent to. 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_mcast multicasts a message stored in the active send buffer to ntask tasks specified in the tids array. The message is not sent to the caller even if listed in the array of tids. The content of the message can be distinguished by msgtag. If pvm_mcast is suc- cessful, info will be 0. If some error occurs then info will be < 0. The receiving processes can call either pvm_recv or pvm_nrecv to receive their copy of the multicast. pvm_mcast is asynchronous and based on a minimum spanning tree algorithm between the pvmds. 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 the matching receive is executed by the receiving processor. pvm_mcast first determines which other pvmds contain the specified tasks. Then passes the message to these pvmds which in turn distribute the message to their local tasks without further network traffic. Multicasting is not supported by most multiprocessor vendors. Typically their native calls only support broadcasting to {m all the user's processes on a multiprocessor. Because of this omission, pvm_mcast may not be an efficient communication method on some multiprocessors except in the special case of broadcasting to all PVM processes. EXAMPLES
C: info = pvm_initsend( PvmDataRaw ); info = pvm_pkint( array, 10, 1 ); msgtag = 5 ; info = pvm_mcast( tids, ntask, msgtag ); Fortran: CALL PVMFINITSEND(PVMDEFAULT) CALL PVMFPACK( REAL4, DATA, 100, 1, INFO ) CALL PVMFMCAST( NPROC, TIDS, 5, INFO ) ERRORS
These error conditions can be returned by pvm_mcast PvmBadParam giving a msgtag < 0. PvmSysErr pvmd not responding. PvmNoBuf no send buffer. SEE ALSO
pvm_psend(3PVM), pvm_recv(3PVM), pvm_send(3PVM) 30 August, 1993 MCAST(3PVM)
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