Routines for exercises

pvmfexit(info)

info: integer status code returned by the routine. Values less than zero indicate an error.

This routine tells the local PVM daemon that the calling process is leaving PVM. The routine does not kill the process, which can continue to perform like any other serial process. The routine should also be called by all PVM processes before they stop or exit. It must be called by processes that were not started with pvmfspawn; otherwise PVM will not know if the process has crashed or left normally.

pvmfinitsend(encoding, bufid)

encoding

integer specifying the next message's encoding scheme. Options are:

PVMDEFAULT: XDR if heterogeneous
PVMRAW: no coding
PVMINPLACE: data left in place

bufid

integer returned containing the message buffer identifier. Values less than zero indicate an error.

This routine clears the send buffer and prepares it for packing a new message.

pvmfmcast(ntask, tids, msgtag, info)

ntask

integer specifying the number of tasks to which messages are sent.

tids

integer array of length at least ntask containing the task IDs of the tasks to which messages are to be sent.

msgtag

integer message tag supplied by the user - should be greater than or equal to zero.

info

integer status code returned by the routine. Values less than zero indicate an error. This routine multi-casts a message stored in the active send buffer to ntask tasks specified in the tids array. The receiving processes can call pvmfrecv to receive their copy of the multi-cast. pvmfmcast is asynchronous and computation on the sending processor resumes as soon as the message has been sent.

pvmfmytid(tid)

tid: integer task identifier of the calling PVM process. Value less than zero indicates an error.

This routine must be the first PVM call in any program using PVM 3.0. The routine enrolls the calling process into PVM on its first call. It also generates a unique tid if this process was not created by pvmfspawn.

pvmfpack(what, xp, nitem, stride, info)

what

integer specifying the type of data being packed. Options are:

string
real4
byte1
complex8
integer2
real8
integer4
complex16

xp

Pointer to the beginning of a block of bytes.

nitem

The total number of items to be packed.

stride

The stride to be used when packing items.

info

Integer status code returned by routine. Values less than zero indicate an error.

Packs an array of the given data type into the active send buffer.

pvmfparent(tid)

tid

pvmfrecv(tid, msgtag, bufid)

tid: integer task identifier of sending process, supplied by user. -1 is a wildcard and matches any tid.
msgtag: integer message tag supplied by user - should be >=0. -1 matches any message tag.
bufid: integer returns the value of the new active receive buffer identifier. Values less than zero indicate an error.

This routine "blocks" the process until a message with label msgtag arrives from tid. The routine then places the message in a new active receive buffer which also clears the current receive buffer.

pvmfsend(tid, msgtag, info)

tid: integer task indentifier of destination process.
msgtag: integer message tag supplied by the user - should be >=0.
info: integer status code returned by the routine. Values less than zero indicate an error.

This routine sends a message stored in the active buffer to the PVM process identified by tid. msgtag is used to label the message.

The routine is asynchronous so computation on the sending processor resumes as soon as the message has been sent.

pvmfserror(set, oldset)

set: integer defining whether error detection is to be turned on (1) or off (0).
oldset: integer defining the previous setting of pvmfserror.

This routine sets automatic printing of error messages for all subsequent PVM calls by the calling process.

pvmfspawn(task, flag, where, ntask, tids, numt)

task

character string containing the executable file name of the PVM process to be started. The executable must already reside on the host on which it is to be started.

flag

integer specifying spawn options from:

PVMDEFAULT: PVM chooses any machine
PVMHOST: the where argument specifies host
PVMARCH: where specifies architecture type
PVMDEBUG: start up processes under debugger
PVMTRACE: processes will generate trace data (for future expansion)

Use sum of these where appropriate e.g. PVMDEFAULT+PVMDEBUG

where

character string specifying where to start the PVM process. where can be host name or a PVM architecture class. If flag is *, PVM ignores where and selects most appropriate host.

ntask

integer specifying the number of copies of the executable to start.

tids

integer array of length ntask. On return the array contains tids of the PVM processes started by this call. Error code is generated in the array if there is a error starting a given task.

numt

integer returning the actual number of tasks started.

This routine starts ntask copies of the executable named task. If PVMDEBUG is set, then the PVM daemon will start the task(s) under a debugger. Debugger is a shell script that users can modify. Presently the script starts an xterm with dbx.

pvmfunpack(what, xp, nitem, stride, info)

The arguments are defined in the pvmfpack routine.

xp: Pointer to the beginning of a block of bytes - memory location into which data is to be unpacked.

Messages should be unpacked as they were packed to ensure data integrity.

Submitted by Mark Johnston,
last updated on 19 January 1995.