PROBE(3PVM) PVM Version 3.4 PROBE(3PVM)NAMEpvm_probe - Check if message has arrived.
SYNOPSIS
C int bufid = pvm_probe( int tid, int msgtag )
Fortran call pvmfprobe( tid, msgtag, bufid )
PARAMETERS
tid Integer task identifier of sending process supplied by the
user.
msgtag Integer message tag supplied by the user. msgtag should be >=
0.
bufid Integer returning the value of the new active receive buffer
identifier. Values less than zero indicate an error.
DESCRIPTION
The routine pvm_probe checks to see if a message with label msgtag has
arrived from tid. If a matching message has arrived pvm_probe returns
a buffer identifier in bufid. This bufid can be used with pvm_bufinfo
to determine information about the message such as its source and
length.
If the requested message has not arrived, then pvm_probe returns with a
0 in bufid. If some error occurs bufid will be < 0.
A -1 in msgtag or tid matches anything. This allows the user the fol‐
lowing options. If tid = -1 and msgtag is defined by the user, then
pvm_probe will accept a message from any process which has a matching
msgtag. If msgtag = -1 and tid is defined by the user, then pvm_probe
will accept any message that is sent from process tid. If tid = -1 and
msgtag = -1, then pvm_probe will accept any message from any process.
pvm_probe can be called multiple times to check if a given message has
arrived yet. After the message has arrived, pvm_recv must be called
before the message can be unpacked into the user's memory using the
unpack routines.
EXAMPLES
C:
tid = pvm_parent();
msgtag = 4 ;
arrived = pvm_probe( tid, msgtag );
if ( arrived )
info = pvm_bufinfo( arrived, &len, &tag, &tid );
else
/* go do other computing */
Fortran:
CALL PVMFPROBE( -1, 4, ARRIVED )
IF ( ARRIVED .GT. 0 ) THEN
CALL PVMFBUFINFO( ARRIVED, LEN, TAG, TID, INFO )
ELSE
* GO DO USEFUL WORK
ENDIF
ERRORS
These error conditions can be returned by pvm_probe.
PvmBadParam
giving an invalid tid value or msgtag.
PvmSysErr
pvmd not responding.
SEE ALSOpvm_bufinfo(3PVM), pvm_getminfo(3PVM), pvm_nrecv(3PVM), pvm_recv(3PVM),
pvm_unpack(3PVM)
30 August, 1993 PROBE(3PVM)
