pvm_initsend(3)

1INITSEND(3PVM)                  PVM Version 3.4                 INITSEND(3PVM)
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NAME

6       pvm_initsend - Clear default send buffer and specify message encoding.
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SYNOPSIS

10       C    int bufid = pvm_initsend( int encoding )
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12       Fortran   call pvmfinitsend( encoding, bufid )
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PARAMETERS

16       encoding
17               Integer specifying the next message's encoding scheme.
18               Options in C are:
19                    Encoding value           MEANING
20                    PvmDataDefault      0    XDR
21                    PvmDataRaw          1    no encoding
22                    PvmDataInPlace      2    data left in place
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24               Option names are in Fortran are:
25                    Encoding value           MEANING
26                    PVMDEFAULT          0    XDR
27                    PVMRAW              1    no encoding
28                    PVMINPLACE          2    data left in place
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30       bufid   Integer  returned  containing  the  message  buffer identifier.
31               Values less than zero indicate an error.
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DESCRIPTION

35       The routine pvm_initsend clears the send buffer  and  prepares  it  for
36       packing a new message.  The encoding scheme used for the packing is set
37       by encoding.  XDR encoding is used by default because PVM can not  know
38       if the user is going to add a heterogeneous machine before this message
39       is sent.  If the user knows that the next message will only be sent  to
40       a  machine  that  understands  the  native format, then he can use Pvm‐
41       DataRaw encoding and save on encoding costs.
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43       PvmDataInPlace encoding specifies that data be  left  in  place  during
44       packing.   The  message  buffer only contains the sizes and pointers to
45       the items to be sent. When pvm_send is  called  the  items  are  copied
46       directly  out of the user's memory. This option decreases the number of
47       times a message is copied at the expense of requiring the user  to  not
48       modify the items between the time they are packed and the time they are
49       sent.
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51       If pvm_initsend is successful, then bufid will contain the message buf‐
52       fer identifier.  If some error occurs then bufid will be < 0.
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RESTRICTIONS

56       PvmDataInPlace  allows only dense (stride = 1) data in version 3.3.  It
57       cannot be used on shared memory (*MP) architectures; a PvmNotImpl error
58       will occur at send time.
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EXAMPLES

62       C:
63            bufid = pvm_initsend( PvmDataDefault );
64            info = pvm_pkint( array, 10, 1 );
65            msgtag = 3 ;
66            info = pvm_send( tid, msgtag );
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68       Fortran:
69            CALL PVMFINITSEND(PVMRAW, BUFID)
70            CALL PVMFPACK( REAL4, DATA, 100, 1, INFO )
71            CALL PVMFSEND( TID, 3, INFO )
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ERRORS

75       These error conditions can be returned by pvm_initsend
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77       PvmBadParam
78              giving an invalid encoding value
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80       PvmNoMem
81              Malloc has failed. There is not enough memory to create the buf‐
82              fer
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