PSEND(3PVM) PVM Version 3.4 PSEND(3PVM)NAMEpvm_psend - Pack and send data in one call.
SYNOPSIS
C int info = pvm_psend( int tid, int msgtag, char *buf,
int len, int datatype )
Fortran call pvmfpsend( tid, msgtag, buf, len, datatype,
info )
PARAMETERS
tid Integer task identifier of destination process.
msgtag Integer message tag supplied by the user. msgtag should be >=
0.
buf Pointer to a buffer to send.
len Length of buffer (in multiple of data type size).
datatype
Type of data to which buf points (see below).
info Integer status code returned by the routine.
DESCRIPTION
The routine pvm_psend takes a pointer to a buffer buf its length len
and its data type datatype and sends this data directly to the PVM task
identified by tid. msgtag is used to label the content of the message.
If pvm_psend is successful, info will be 0. If some error occurs then
info will be < 0.
pvm_psend data can be received by pvm_precv, pvm_recv, pvm_trecv, or
pvm_nrecv.
The pvm_psend routine is asynchronous. Computation on the sending pro‐
cessor resumes as soon as the buffer is safe for reuse. 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.
In C the datatype parameter must be one of the following, depending on
the type of data to be sent: [Version 3.3.0 - This parameter only
determines message length, not data conversion. It only sends raw
bytes]
datatype Data Type
PVM_STR string
PVM_BYTE byte
PVM_SHORT short
PVM_INT int
PVM_FLOAT real
PVM_CPLX complex
PVM_DOUBLE double
PVM_DCPLX double complex
PVM_LONG long integer
PVM_USHORT unsigned short int
PVM_UINT unsigned int
PVM_ULONG unsigned long int
In Fortran the same data types specified for pack should be used.
The PVM model guarantees the following about message order. If task 1
sends message A to task 2, then task 1 sends message B to task 2, mes‐
sage A will arrive at task 2 before message B. Moreover, if both mes‐
sages arrive before task 2 does a receive, then a wildcard receive will
always return message A.
pvm_psend does not affect the state of the current outgoing message
buffer (created by pvm_initsend and used by pvm_send).
WARNINGS
In some versions of PVM (CM5, I860 and PGON), messages sent using
pvm_psend must be received only by pvm_precv, likewise those sent with
pvm_send must be received by pvm_recv, pvm_nrecv or pvm_trecv.
pvm_psend is not compatible with pvm_recv (nor pvm_send with
pvm_precv). In addition, pvm_probe is not interoperable with
pvm_psend.
This problem occurs because nonstandard message headers are used for
efficiency in the pvm_psend function. In the generic Unix version of
PVM, the calls are fully interoperable.
The message tag space is shared between pvm_send and pvm_psend, so you
must be careful to avoid selecting the wrong message (for example by
using a wildcard to match the message).
EXAMPLES
C:
info = pvm_psend( tid, msgtag, array, 1000, PVM_FLOAT );
Fortran:
CALL PVMFPSEND( TID, MSGTAG, BUF, CNT, REAL4, INFO )
ERRORS
These error conditions can be returned by pvm_psend
PvmBadParam
giving an invalid tid, msgtag, or datatype.
PvmSysErr
pvmd not responding.
SEE ALSOpvm_precv(3PVM), pvm_send(3PVM)
15 March, 1994 PSEND(3PVM)
