NAME

       pvm_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 PvmDataRaw 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 buffer 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 buffer

SEE ALSO

       pvm_mkbuf(3PVM)

                                         30 August, 1993                           INITSEND(3PVM)