INITSEND(3PVM) PVM Version 3.4 INITSEND(3PVM)NAMEpvm_initsend - Clear default send buffer and specify message encoding.
SYNOPSIS
C int bufid = pvm_initsend( int encoding )
Fortran call pvmfinitsend( encoding, bufid )
PARAMETERS
encoding
Integer specifying the next message's encoding scheme.
Options in C are:
Encoding value MEANING
PvmDataDefault 0 XDR
PvmDataRaw 1 no encoding
PvmDataInPlace 2 data left in place
Option names are in Fortran are:
Encoding value MEANING
PVMDEFAULT 0 XDR
PVMRAW 1 no encoding
PVMINPLACE 2 data left in place
bufid Integer returned containing the message buffer identifier.
Values less than zero indicate an error.
DESCRIPTION
The routine pvm_initsend clears the send buffer and prepares it for
packing a new message. The encoding scheme used for the packing is set
by encoding. XDR encoding is used by default because PVM can not know
if the user is going to add a heterogeneous machine before this message
is sent. If the user knows that the next message will only be sent to
a machine that understands the native format, then he can use Pvm‐
DataRaw encoding and save on encoding costs.
PvmDataInPlace encoding specifies that data be left in place during
packing. The message buffer only contains the sizes and pointers to
the items to be sent. When pvm_send is called the items are copied
directly out of the user's memory. This option decreases the number of
times a message is copied at the expense of requiring the user to not
modify the items between the time they are packed and the time they are
sent.
If pvm_initsend is successful, then bufid will contain the message buf‐
fer identifier. If some error occurs then bufid will be < 0.
RESTRICTIONS
PvmDataInPlace allows only dense (stride = 1) data in version 3.3. It
cannot be used on shared memory (*MP) architectures; a PvmNotImpl error
will occur at send time.
EXAMPLES
C:
bufid = pvm_initsend( PvmDataDefault );
info = pvm_pkint( array, 10, 1 );
msgtag = 3 ;
info = pvm_send( tid, msgtag );
Fortran:
CALL PVMFINITSEND(PVMRAW, BUFID)
CALL PVMFPACK( REAL4, DATA, 100, 1, INFO )
CALL PVMFSEND( TID, 3, INFO )
ERRORS
These error conditions can be returned by pvm_initsend
PvmBadParam
giving an invalid encoding value
PvmNoMem
Malloc has failed. There is not enough memory to create the buf‐
fer
SEE ALSOpvm_mkbuf(3PVM)
30 August, 1993 INITSEND(3PVM)
