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)