pvm_initsend(3pvm) [redhat man page]

INITSEND(3PVM)							  PVM Version 3.4						    INITSEND(3PVM)

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 mes-
       sage  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)

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FREEBUF(3PVM)							  PVM Version 3.4						     FREEBUF(3PVM)

NAME

       pvm_freebuf - Disposes of a message buffer.

SYNOPSIS

       C    int info = pvm_freebuf( int bufid )

       Fortran	 call pvmffreebuf( bufid, info )

PARAMETERS

       bufid   Integer message buffer identifier.

       info    Integer status code returned by the routine.  Values less than zero indicate an error.

DESCRIPTION

       The routine pvm_freebuf frees the memory associated with the message buffer identified by bufid.  Message buffers are created by pvm_mkbuf,
       pvm_initsend, and pvm_recv.  If pvm_freebuf is successful, info will be 0.  If some error occurs then info will be < 0.

       pvm_freebuf can be called for a send buffer created by pvm_mkbuf after the message has been sent and is no longer needed.

       Receive buffers typically do not have to be freed unless they have been saved in the course of using multiple buffers.  But pvm_freebuf can
       be  used  to  destroy  receive buffers as well.	So messages that arrive but are no longer needed can be destroyed so they will not consume
       buffer space.

       Typically multiple send and receive buffers are not needed and the user can simply use the pvm_initsend routine to reset the  default  send
       buffer.

       There  are  several  cases  where multiple buffers are useful.  One example where multiple message buffers are needed involves libraries or
       graphical interfaces that use PVM and interact with a running PVM application but do not want to interfere with the application's own  com-
       munication.

       When  multiple  buffers	are  used  they generally are made and freed for each message that is packed.  In fact, pvm_initsend simply does a
       pvm_freebuf followed by a pvm_mkbuf for the default buffer.

EXAMPLES

       C:
	    bufid = pvm_mkbuf( PvmDataDefault );
		  :
	    info = pvm_freebuf( bufid );

       Fortran:
	    CALL PVMFMKBUF( PVMDEFAULT, BUFID )
		  :
	    CALL PVMFFREEBUF( BUFID, INFO )

ERRORS

       These error conditions can be returned by pvm_freebuf

       PvmBadParam
	      giving an invalid argument value.

       PvmNoSuchBuf
	      giving an invalid bufid value.

SEE ALSO

       pvm_mkbuf(3PVM), pvm_initsend(3PVM), pvm_recv(3PVM)

								  30 August, 1993						     FREEBUF(3PVM)

Linux and UNIX Man Pages

pvm_initsend(3pvm) [redhat man page]

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